diff --git a/browser/base/content/browser.css b/browser/base/content/browser.css
index 7557d15a15..f03f21c3f7 100644
--- a/browser/base/content/browser.css
+++ b/browser/base/content/browser.css
@@ -557,7 +557,7 @@ toolbar:not(#TabsToolbar) > #personal-bookmarks {
   transition: none;
 }
 
-#DateTimePickerPanel {
+#DateTimePickerPanel[active="true"] {
   -moz-binding: url("chrome://global/content/bindings/datetimepopup.xml#datetime-popup");
 }
 
diff --git a/browser/base/content/browser.xul b/browser/base/content/browser.xul
index 9a4fa0fd52..e8567eb5c2 100644
--- a/browser/base/content/browser.xul
+++ b/browser/base/content/browser.xul
@@ -160,8 +160,10 @@
            hidden="true"
            orient="vertical"
            noautofocus="true"
+           noautohide="true"
            consumeoutsideclicks="false"
-           level="parent">
+           level="parent"
+           tabspecific="true">
       <iframe id="dateTimePopupFrame"/>
     </panel>
 
diff --git a/dom/html/HTMLInputElement.cpp b/dom/html/HTMLInputElement.cpp
index e8a4af454c..62f194493a 100644
--- a/dom/html/HTMLInputElement.cpp
+++ b/dom/html/HTMLInputElement.cpp
@@ -543,9 +543,8 @@ GetDOMFileOrDirectoryPath(const OwningFileOrDirectory& aData,
 bool
 HTMLInputElement::ValueAsDateEnabled(JSContext* cx, JSObject* obj)
 {
-  return Preferences::GetBool("dom.experimental_forms", false) ||
-    Preferences::GetBool("dom.forms.datepicker", false) ||
-    Preferences::GetBool("dom.forms.datetime", false);
+  return IsExperimentalFormsEnabled() || IsDatePickerEnabled() ||
+         IsInputDateTimeEnabled();
 }
 
 NS_IMETHODIMP
@@ -628,7 +627,7 @@ HTMLInputElement::nsFilePickerShownCallback::Done(int16_t aResult)
   RefPtr<DispatchChangeEventCallback> dispatchChangeEventCallback =
     new DispatchChangeEventCallback(mInput);
 
-  if (Preferences::GetBool("dom.webkitBlink.dirPicker.enabled", false) &&
+  if (IsWebkitDirPickerEnabled() &&
       mInput->HasAttr(kNameSpaceID_None, nsGkAtoms::webkitdirectory)) {
     ErrorResult error;
     GetFilesHelper* helper = mInput->GetOrCreateGetFilesHelper(true, error);
@@ -827,7 +826,7 @@ HTMLInputElement::IsPopupBlocked() const
 nsresult
 HTMLInputElement::InitDatePicker()
 {
-  if (!Preferences::GetBool("dom.forms.datepicker", false)) {
+  if (!IsDatePickerEnabled()) {
     return NS_OK;
   }
 
@@ -2516,10 +2515,8 @@ bool
 HTMLInputElement::IsExperimentalMobileType(uint8_t aType)
 {
   return (aType == NS_FORM_INPUT_DATE &&
-    !Preferences::GetBool("dom.forms.datetime", false) &&
-    !Preferences::GetBool("dom.forms.datepicker", false)) ||
-    (aType == NS_FORM_INPUT_TIME &&
-     !Preferences::GetBool("dom.forms.datetime", false));
+    !IsInputDateTimeEnabled() && !IsDatePickerEnabled()) ||
+    (aType == NS_FORM_INPUT_TIME && !IsInputDateTimeEnabled());
 }
 
 bool
@@ -3025,8 +3022,8 @@ HTMLInputElement::GetDisplayFileName(nsAString& aValue) const
   nsXPIDLString value;
 
   if (mFilesOrDirectories.IsEmpty()) {
-    if ((Preferences::GetBool("dom.input.dirpicker", false) && Allowdirs()) ||
-        (Preferences::GetBool("dom.webkitBlink.dirPicker.enabled", false) &&
+    if ((IsDirPickerEnabled() && Allowdirs()) ||
+        (IsWebkitDirPickerEnabled() &&
          HasAttr(kNameSpaceID_None, nsGkAtoms::webkitdirectory))) {
       nsContentUtils::GetLocalizedString(nsContentUtils::eFORMS_PROPERTIES,
                                          "NoDirSelected", value);
@@ -3055,7 +3052,7 @@ HTMLInputElement::SetFilesOrDirectories(const nsTArray<OwningFileOrDirectory>& a
 {
   ClearGetFilesHelpers();
 
-  if (Preferences::GetBool("dom.webkitBlink.filesystem.enabled", false)) {
+  if (IsWebkitFileSystemEnabled()) {
     HTMLInputElementBinding::ClearCachedWebkitEntriesValue(this);
     mEntries.Clear();
   }
@@ -3074,7 +3071,7 @@ HTMLInputElement::SetFiles(nsIDOMFileList* aFiles,
   mFilesOrDirectories.Clear();
   ClearGetFilesHelpers();
 
-  if (Preferences::GetBool("dom.webkitBlink.filesystem.enabled", false)) {
+  if (IsWebkitFileSystemEnabled()) {
     HTMLInputElementBinding::ClearCachedWebkitEntriesValue(this);
     mEntries.Clear();
   }
@@ -3097,14 +3094,14 @@ HTMLInputElement::MozSetDndFilesAndDirectories(const nsTArray<OwningFileOrDirect
 {
   SetFilesOrDirectories(aFilesOrDirectories, true);
 
-  if (Preferences::GetBool("dom.webkitBlink.filesystem.enabled", false)) {
+  if (IsWebkitFileSystemEnabled()) {
     UpdateEntries(aFilesOrDirectories);
   }
 
   RefPtr<DispatchChangeEventCallback> dispatchChangeEventCallback =
     new DispatchChangeEventCallback(this);
 
-  if (Preferences::GetBool("dom.webkitBlink.dirPicker.enabled", false) &&
+  if (IsWebkitDirPickerEnabled() &&
       HasAttr(kNameSpaceID_None, nsGkAtoms::webkitdirectory)) {
     ErrorResult rv;
     GetFilesHelper* helper = GetOrCreateGetFilesHelper(true /* recursionFlag */,
@@ -3182,8 +3179,8 @@ HTMLInputElement::GetFiles()
     return nullptr;
   }
 
-  if (Preferences::GetBool("dom.input.dirpicker", false) && Allowdirs() &&
-      (!Preferences::GetBool("dom.webkitBlink.dirPicker.enabled", false) ||
+  if (IsDirPickerEnabled() && Allowdirs() &&
+      (!IsWebkitDirPickerEnabled() ||
        !HasAttr(kNameSpaceID_None, nsGkAtoms::webkitdirectory))) {
     return nullptr;
   }
@@ -4366,8 +4363,8 @@ HTMLInputElement::MaybeInitPickers(EventChainPostVisitor& aVisitor)
       do_QueryInterface(aVisitor.mEvent->mOriginalTarget);
     if (target &&
         target->FindFirstNonChromeOnlyAccessContent() == this &&
-        ((Preferences::GetBool("dom.input.dirpicker", false) && Allowdirs()) ||
-         (Preferences::GetBool("dom.webkitBlink.dirPicker.enabled", false) &&
+        ((IsDirPickerEnabled() && Allowdirs()) ||
+         (IsWebkitDirPickerEnabled() &&
           HasAttr(kNameSpaceID_None, nsGkAtoms::webkitdirectory)))) {
       type = FILE_PICKER_DIRECTORY;
     }
@@ -5735,20 +5732,133 @@ HTMLInputElement::ParseTime(const nsAString& aValue, uint32_t* aResult)
   return true;
 }
 
-static bool
-IsDateTimeEnabled(int32_t aNewType)
+/* static */ bool
+HTMLInputElement::IsDateTimeTypeSupported(uint8_t aDateTimeInputType)
 {
-  return (aNewType == NS_FORM_INPUT_DATE &&
-          (Preferences::GetBool("dom.forms.datetime", false) ||
-           Preferences::GetBool("dom.experimental_forms", false) ||
-           Preferences::GetBool("dom.forms.datepicker", false))) ||
-         (aNewType == NS_FORM_INPUT_TIME &&
-          (Preferences::GetBool("dom.forms.datetime", false) ||
-           Preferences::GetBool("dom.experimental_forms", false))) ||
-         ((aNewType == NS_FORM_INPUT_MONTH ||
-           aNewType == NS_FORM_INPUT_WEEK ||
-           aNewType == NS_FORM_INPUT_DATETIME_LOCAL) &&
-          Preferences::GetBool("dom.forms.datetime", false));
+  return (aDateTimeInputType == NS_FORM_INPUT_DATE &&
+          (IsInputDateTimeEnabled() || IsExperimentalFormsEnabled() ||
+           IsDatePickerEnabled())) ||
+         (aDateTimeInputType == NS_FORM_INPUT_TIME &&
+          (IsInputDateTimeEnabled() || IsExperimentalFormsEnabled())) ||
+         ((aDateTimeInputType == NS_FORM_INPUT_MONTH ||
+           aDateTimeInputType == NS_FORM_INPUT_WEEK ||
+           aDateTimeInputType == NS_FORM_INPUT_DATETIME_LOCAL) &&
+          IsInputDateTimeEnabled());
+}
+
+/* static */ bool
+HTMLInputElement::IsWebkitDirPickerEnabled()
+{
+  static bool sWebkitDirPickerEnabled = false;
+  static bool sWebkitDirPickerPrefCached = false;
+  if (!sWebkitDirPickerPrefCached) {
+    sWebkitDirPickerPrefCached = true;
+    Preferences::AddBoolVarCache(&sWebkitDirPickerEnabled,
+                                 "dom.webkitBlink.dirPicker.enabled",
+                                 false);
+  }
+
+  return sWebkitDirPickerEnabled;
+}
+
+/* static */ bool
+HTMLInputElement::IsWebkitFileSystemEnabled()
+{
+  static bool sWebkitFileSystemEnabled = false;
+  static bool sWebkitFileSystemPrefCached = false;
+  if (!sWebkitFileSystemPrefCached) {
+    sWebkitFileSystemPrefCached = true;
+    Preferences::AddBoolVarCache(&sWebkitFileSystemEnabled,
+                                 "dom.webkitBlink.filesystem.enabled",
+                                 false);
+  }
+
+  return sWebkitFileSystemEnabled;
+}
+
+/* static */ bool
+HTMLInputElement::IsDirPickerEnabled()
+{
+  static bool sDirPickerEnabled = false;
+  static bool sDirPickerPrefCached = false;
+  if (!sDirPickerPrefCached) {
+    sDirPickerPrefCached = true;
+    Preferences::AddBoolVarCache(&sDirPickerEnabled, "dom.input.dirpicker",
+                                 false);
+  }
+
+  return sDirPickerEnabled;
+}
+
+/* static */ bool
+HTMLInputElement::IsDatePickerEnabled()
+{
+  static bool sDatePickerEnabled = false;
+  static bool sDatePickerPrefCached = false;
+  if (!sDatePickerPrefCached) {
+    sDatePickerPrefCached = true;
+    Preferences::AddBoolVarCache(&sDatePickerEnabled, "dom.forms.datepicker",
+                                 false);
+  }
+
+  return sDatePickerEnabled;
+}
+
+/* static */ bool
+HTMLInputElement::IsExperimentalFormsEnabled()
+{
+  static bool sExperimentalFormsEnabled = false;
+  static bool sExperimentalFormsPrefCached = false;
+  if (!sExperimentalFormsPrefCached) {
+    sExperimentalFormsPrefCached = true;
+    Preferences::AddBoolVarCache(&sExperimentalFormsEnabled,
+                                 "dom.experimental_forms",
+                                 false);
+  }
+
+  return sExperimentalFormsEnabled;
+}
+
+/* static */ bool
+HTMLInputElement::IsInputDateTimeEnabled()
+{
+  static bool sDateTimeEnabled = false;
+  static bool sDateTimePrefCached = false;
+  if (!sDateTimePrefCached) {
+    sDateTimePrefCached = true;
+    Preferences::AddBoolVarCache(&sDateTimeEnabled, "dom.forms.datetime",
+                                 false);
+  }
+
+  return sDateTimeEnabled;
+}
+
+/* static */ bool
+HTMLInputElement::IsInputNumberEnabled()
+{
+  static bool sInputNumberEnabled = false;
+  static bool sInputNumberPrefCached = false;
+  if (!sInputNumberPrefCached) {
+    sInputNumberPrefCached = true;
+    Preferences::AddBoolVarCache(&sInputNumberEnabled, "dom.forms.number",
+                                 false);
+  }
+
+  return sInputNumberEnabled;
+}
+
+/* static */ bool
+HTMLInputElement::IsInputColorEnabled()
+{
+  static bool sInputColorEnabled = false;
+  static bool sInputColorPrefCached = false;
+  if (!sInputColorPrefCached) {
+    sInputColorPrefCached = true;
+    Preferences::AddBoolVarCache(&sInputColorEnabled, "dom.forms.color",
+                                 false);
+  }
+
+  return sInputColorEnabled;
 }
 
 bool
@@ -5766,12 +5876,11 @@ HTMLInputElement::ParseAttribute(int32_t aNamespaceID,
       if (success) {
         newType = aResult.GetEnumValue();
         if ((IsExperimentalMobileType(newType) &&
-             !Preferences::GetBool("dom.experimental_forms", false)) ||
-            (newType == NS_FORM_INPUT_NUMBER &&
-             !Preferences::GetBool("dom.forms.number", false)) ||
-            (newType == NS_FORM_INPUT_COLOR &&
-             !Preferences::GetBool("dom.forms.color", false)) ||
-            (IsDateTimeInputType(newType) && !IsDateTimeEnabled(newType))) {
+             !IsExperimentalFormsEnabled()) ||
+            (newType == NS_FORM_INPUT_NUMBER && !IsInputNumberEnabled()) ||
+            (newType == NS_FORM_INPUT_COLOR && !IsInputColorEnabled()) ||
+            (IsDateTimeInputType(newType) &&
+             !IsDateTimeTypeSupported(newType))) {
           newType = kInputDefaultType->value;
           aResult.SetTo(newType, &aValue);
         }
diff --git a/dom/html/HTMLInputElement.h b/dom/html/HTMLInputElement.h
index 9ca876aee8..9baaffb63e 100644
--- a/dom/html/HTMLInputElement.h
+++ b/dom/html/HTMLInputElement.h
@@ -1632,9 +1632,73 @@ private:
     return IsSingleLineTextControl(false, aType) ||
            aType == NS_FORM_INPUT_RANGE ||
            aType == NS_FORM_INPUT_NUMBER ||
-           aType == NS_FORM_INPUT_TIME;
+           aType == NS_FORM_INPUT_TIME ||
+           aType == NS_FORM_INPUT_DATE;
   }
 
+  /**
+   * Checks if aDateTimeInputType should be supported based on "dom.forms.datetime",
+   * "dom.forms.datepicker" and "dom.experimental_forms".
+   */
+  static bool
+  IsDateTimeTypeSupported(uint8_t aDateTimeInputType);
+
+  /**
+   * Checks preference "dom.webkitBlink.dirPicker.enabled" to determine if
+   * webkitdirectory should be supported.
+   */
+  static bool
+  IsWebkitDirPickerEnabled();
+
+  /**
+   * Checks preference "dom.webkitBlink.filesystem.enabled" to determine if
+   * webkitEntries should be supported.
+   */
+  static bool
+  IsWebkitFileSystemEnabled();
+
+  /**
+   * Checks preference "dom.input.dirpicker" to determine if file and directory
+   * entries API should be supported.
+   */
+  static bool
+  IsDirPickerEnabled();
+
+  /**
+   * Checks preference "dom.forms.datepicker" to determine if date picker should
+   * be supported.
+   */
+  static bool
+  IsDatePickerEnabled();
+
+  /**
+   * Checks preference "dom.experimental_forms" to determine if experimental
+   * implementation of input element should be enabled.
+   */
+  static bool
+  IsExperimentalFormsEnabled();
+
+  /**
+   * Checks preference "dom.forms.datetime" to determine if input date/time
+   * related types should be supported.
+   */
+  static bool
+  IsInputDateTimeEnabled();
+
+  /**
+   * Checks preference "dom.forms.number" to determine if input type=number
+   * should be supported.
+   */
+  static bool
+  IsInputNumberEnabled();
+
+  /**
+   * Checks preference "dom.forms.color" to determine if date/time related
+   * types should be supported.
+   */
+  static bool
+  IsInputColorEnabled();
+
   struct nsFilePickerFilter {
     nsFilePickerFilter()
       : mFilterMask(0) {}
diff --git a/dom/html/test/forms/mochitest.ini b/dom/html/test/forms/mochitest.ini
index 6fceefd981..199e4baf80 100644
--- a/dom/html/test/forms/mochitest.ini
+++ b/dom/html/test/forms/mochitest.ini
@@ -32,6 +32,8 @@ skip-if = android_version == '18' # Android, bug 1147974
 skip-if = android_version == '18' # Android, bug 1147974
 [test_input_date_key_events.html]
 skip-if = os == "android"
+[test_input_datetime_input_change_events.html]
+skip-if = os == "android"
 [test_input_datetime_focus_blur.html]
 skip-if = os == "android"
 [test_input_datetime_focus_blur_events.html]
diff --git a/dom/html/test/forms/test_input_date_key_events.html b/dom/html/test/forms/test_input_date_key_events.html
index cd974e5057..f502d6a4d6 100644
--- a/dom/html/test/forms/test_input_date_key_events.html
+++ b/dom/html/test/forms/test_input_date_key_events.html
@@ -184,16 +184,16 @@ var testData = [
     expectedVal: "2016-01-31"
   },
   {
-    // Home key on year field sets it to the minimum year, which is 0001.
+    // Home key should have no effect on year field.
     keys: ["VK_TAB", "VK_TAB", "VK_HOME"],
     initialVal: "2016-01-01",
-    expectedVal: "0001-01-01"
+    expectedVal: "2016-01-01"
   },
   {
-    // End key on year field sets it to the maximum year, which is 275760.
+    // End key should have no effect on year field.
     keys: ["VK_TAB", "VK_TAB", "VK_END"],
     initialVal: "2016-01-01",
-    expectedVal: "275760-01-01"
+    expectedVal: "2016-01-01"
   },
 ];
 
diff --git a/dom/html/test/forms/test_input_datetime_input_change_events.html b/dom/html/test/forms/test_input_datetime_input_change_events.html
new file mode 100644
index 0000000000..e636995d36
--- /dev/null
+++ b/dom/html/test/forms/test_input_datetime_input_change_events.html
@@ -0,0 +1,88 @@
+<!DOCTYPE HTML>
+<html>
+<!--
+https://bugzilla.mozilla.org/show_bug.cgi?id=1370858
+-->
+<head>
+<title>Test for Bug 1370858</title>
+<script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+<script type="application/javascript" src="/tests/SimpleTest/EventUtils.js"></script>
+<link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+</head>
+<body>
+<a target="_blank" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1370858">Mozilla Bug 722599</a>
+<p id="display"></p>
+<div id="content">
+<input type="time" id="input_time" onchange="++changeEvents[0]"
+                                   oninput="++inputEvents[0]">
+<input type="date" id="input_date" onchange="++changeEvents[1]"
+                                   oninput="++inputEvents[1]">
+</div>
+<pre id="test">
+<script class="testbody" type="text/javascript">
+
+/**
+ * Test for Bug 1370858.
+ * Test that change and input events are (not) fired for date/time inputs.
+ **/
+
+var inputTypes = ["time", "date"];
+var changeEvents = [0, 0];
+var inputEvents = [0, 0];
+var values = ["10:30", "2017-06-08"];
+var expectedValues = [["09:30", "01:30"], ["2017-05-08", "2017-01-08"]];
+
+SimpleTest.waitForExplicitFinish();
+SimpleTest.waitForFocus(function() {
+  test();
+  SimpleTest.finish();
+});
+
+function test() {
+  for (var i = 0; i < inputTypes.length; i++) {
+    var input = document.getElementById("input_" + inputTypes[i]);
+    var inputRect = input.getBoundingClientRect();
+
+    // Points over the input's reset button
+    var resetButton_X = inputRect.width - 15;
+    var resetButton_Y = inputRect.height / 2;
+
+    is(changeEvents[i], 0, "Number of change events should be 0 at start.");
+    is(inputEvents[i], 0, "Number of input events should be 0 at start.");
+
+    // Test that change and input events are not dispatched setting .value by
+    // script.
+    input.value = values[i];
+    is(input.value, values[i], "Check that value was set correctly (0).");
+    is(changeEvents[i], 0, "Change event should not have dispatched (0).");
+    is(inputEvents[i], 0, "Input event should not have dispatched (0).");
+
+    // Test that change and input events are fired when changing the value using
+    // up/down keys.
+    input.focus();
+    synthesizeKey("VK_DOWN", {});
+    is(input.value, expectedValues[i][0], "Check that value was set correctly (1).");
+    is(changeEvents[i], 1, "Change event should be dispatched (1).");
+    is(inputEvents[i], 1, "Input event should ne dispatched (1).");
+
+    // Test that change and input events are fired when changing the value with
+    // the keyboard.
+    synthesizeKey("0", {});
+    synthesizeKey("1", {});
+    is(input.value, expectedValues[i][1], "Check that value was set correctly (2).");
+    is(changeEvents[i], 2, "Change event should be dispatched (2).");
+    is(inputEvents[i], 2, "Input event should be dispatched (2).");
+
+    // Test that change and input events are fired when clearing the value using
+    // the reset button.
+    synthesizeMouse(input, resetButton_X, resetButton_Y, {});
+    is(input.value, "", "Check that value was set correctly (3).");
+    is(changeEvents[i], 3, "Change event should be dispatched (3).");
+    is(inputEvents[i], 3, "Input event should be dispatched (3).");
+  }
+}
+
+</script>
+</pre>
+</body>
+</html>
diff --git a/layout/reftests/forms/input/datetime/reftest.list b/layout/reftests/forms/input/datetime/reftest.list
index 0ce2002bd3..a62d56c7c8 100644
--- a/layout/reftests/forms/input/datetime/reftest.list
+++ b/layout/reftests/forms/input/datetime/reftest.list
@@ -11,3 +11,14 @@ skip-if(!Android&&!B2G&&!Mulet) == time-simple-unthemed.html time-simple-untheme
 # type change
 skip-if(Android||B2G||Mulet) == to-time-from-other-type-unthemed.html time-simple-unthemed.html
 skip-if(Android||B2G||Mulet) == from-time-to-other-type-unthemed.html from-time-to-other-type-unthemed-ref.html
+
+# content should not overflow on small width/height
+skip-if(Android) == time-small-width.html time-small-width-ref.html
+skip-if(Android) == time-small-height.html time-small-height-ref.html
+skip-if(Android) == time-small-width-height.html time-small-width-height-ref.html
+
+# content (text) should be left aligned
+skip-if(Android) == time-content-left-aligned.html time-content-left-aligned-ref.html
+
+# reset button should be right aligned
+skip-if(Android) fails-if(styloVsGecko) == time-reset-button-right-aligned.html time-reset-button-right-aligned-ref.html # bug 1372062
diff --git a/layout/reftests/forms/input/datetime/time-content-left-aligned-ref.html b/layout/reftests/forms/input/datetime/time-content-left-aligned-ref.html
new file mode 100644
index 0000000000..ad8be9adc1
--- /dev/null
+++ b/layout/reftests/forms/input/datetime/time-content-left-aligned-ref.html
@@ -0,0 +1,9 @@
+<!DOCTYPE html>
+<html>
+  <body>
+     <input type="time" style="width: 200px;">
+     <!-- div to cover the right area -->
+     <div style="display:block; position:absolute; background-color:black;
+                 top:0px; left:40px; width:200px; height:100px;"></div>
+  </body>
+</html>
diff --git a/layout/reftests/forms/input/datetime/time-content-left-aligned.html b/layout/reftests/forms/input/datetime/time-content-left-aligned.html
new file mode 100644
index 0000000000..aa910cddf9
--- /dev/null
+++ b/layout/reftests/forms/input/datetime/time-content-left-aligned.html
@@ -0,0 +1,9 @@
+<!DOCTYPE html>
+<html>
+  <body>
+     <input type="time" style="width: 50px;">
+     <!-- div to cover the right area -->
+     <div style="display:block; position:absolute; background-color:black;
+                 top:0px; left:40px; width:200px; height:100px;"></div>
+  </body>
+</html>
diff --git a/layout/reftests/forms/input/datetime/time-reset-button-right-aligned-ref.html b/layout/reftests/forms/input/datetime/time-reset-button-right-aligned-ref.html
new file mode 100644
index 0000000000..3d36f20680
--- /dev/null
+++ b/layout/reftests/forms/input/datetime/time-reset-button-right-aligned-ref.html
@@ -0,0 +1,9 @@
+<!DOCTYPE html>
+<html>
+  <body>
+    <input type="time" value="10:00" style="float: right; color: white;">
+    <!-- div to cover the left area -->
+    <div style="display:block; position:absolute; background-color:black;
+                top:0px; right:30px; width:500px; height:100px;"></div>
+  </body>
+</html>
diff --git a/layout/reftests/forms/input/datetime/time-reset-button-right-aligned.html b/layout/reftests/forms/input/datetime/time-reset-button-right-aligned.html
new file mode 100644
index 0000000000..72d5cc140e
--- /dev/null
+++ b/layout/reftests/forms/input/datetime/time-reset-button-right-aligned.html
@@ -0,0 +1,10 @@
+<!DOCTYPE html>
+<html>
+  <body>
+    <input type="time" value="10:00" style="width: 150px; float: right;
+                                            color: white;">
+    <!-- div to cover the left area -->
+    <div style="display:block; position:absolute; background-color:black;
+                top:0px; right:30px; width:500px; height:100px;"></div>
+  </body>
+</html>
diff --git a/layout/reftests/forms/input/datetime/time-small-height-ref.html b/layout/reftests/forms/input/datetime/time-small-height-ref.html
new file mode 100644
index 0000000000..fcda93df9a
--- /dev/null
+++ b/layout/reftests/forms/input/datetime/time-small-height-ref.html
@@ -0,0 +1,18 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <style>
+input {
+  width: 200px;
+  height: 5px;
+  outline: 1px dotted black;
+  /* Disable baseline alignment, so that our y-position isn't influenced by the
+   * choice of font inside of input: */
+  vertical-align: top;
+}
+    </style>
+  </head>
+  <body>
+    <input>
+  </body>
+</html>
diff --git a/layout/reftests/forms/input/datetime/time-small-height.html b/layout/reftests/forms/input/datetime/time-small-height.html
new file mode 100644
index 0000000000..3044822fe8
--- /dev/null
+++ b/layout/reftests/forms/input/datetime/time-small-height.html
@@ -0,0 +1,19 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <style>
+input {
+  width: 200px;
+  height: 5px;
+  outline: 1px dotted black;
+  color: white;
+  /* Disable baseline alignment, so that our y-position isn't influenced by the
+   * choice of font inside of input: */
+  vertical-align: top;
+}
+    </style>
+  </head>
+  <body>
+    <input type="time">
+  </body>
+</html>
diff --git a/layout/reftests/forms/input/datetime/time-small-width-height-ref.html b/layout/reftests/forms/input/datetime/time-small-width-height-ref.html
new file mode 100644
index 0000000000..0979243db0
--- /dev/null
+++ b/layout/reftests/forms/input/datetime/time-small-width-height-ref.html
@@ -0,0 +1,18 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <style>
+input {
+  width: 8px;
+  height: 8px;
+  outline: 1px dotted black;
+  /* Disable baseline alignment, so that our y-position isn't influenced by the
+   * choice of font inside of input: */
+  vertical-align: top;
+}
+    </style>
+  </head>
+  <body>
+    <input>
+  </body>
+</html>
diff --git a/layout/reftests/forms/input/datetime/time-small-width-height.html b/layout/reftests/forms/input/datetime/time-small-width-height.html
new file mode 100644
index 0000000000..a221b28195
--- /dev/null
+++ b/layout/reftests/forms/input/datetime/time-small-width-height.html
@@ -0,0 +1,19 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <style>
+input {
+  width: 8px;
+  height: 8px;
+  outline: 1px dotted black;
+  color: white;
+  /* Disable baseline alignment, so that our y-position isn't influenced by the
+   * choice of font inside of input: */
+  vertical-align: top;
+}
+    </style>
+  </head>
+  <body>
+    <input type="time">
+  </body>
+</html>
diff --git a/layout/reftests/forms/input/datetime/time-small-width-ref.html b/layout/reftests/forms/input/datetime/time-small-width-ref.html
new file mode 100644
index 0000000000..2379c70809
--- /dev/null
+++ b/layout/reftests/forms/input/datetime/time-small-width-ref.html
@@ -0,0 +1,19 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <style>
+input {
+  width: 10px;
+  height: 1.5em;
+  outline: 1px dotted black;
+  background: white;
+  /* Disable baseline alignment, so that our y-position isn't influenced by the
+   * choice of font inside of input: */
+  vertical-align: top;
+}
+    </style>
+  </head>
+  <body>
+    <input>
+  </body>
+</html>
diff --git a/layout/reftests/forms/input/datetime/time-small-width.html b/layout/reftests/forms/input/datetime/time-small-width.html
new file mode 100644
index 0000000000..f76f7fdfa9
--- /dev/null
+++ b/layout/reftests/forms/input/datetime/time-small-width.html
@@ -0,0 +1,20 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <style>
+input {
+  width: 10px;
+  height: 1.5em;
+  outline: 1px dotted black;
+  color: white;
+  background: white;
+  /* Disable baseline alignment, so that our y-position isn't influenced by the
+   * choice of font inside of input: */
+  vertical-align: top;
+}
+    </style>
+  </head>
+  <body>
+    <input type="time">
+  </body>
+</html>
diff --git a/layout/style/res/forms.css b/layout/style/res/forms.css
index f045540b18..e7566e183f 100644
--- a/layout/style/res/forms.css
+++ b/layout/style/res/forms.css
@@ -1135,3 +1135,8 @@ input[type="number"] > div > div > div:hover {
   /* give some indication of hover state for the up/down buttons */
   background-color: lightblue;
 }
+
+input[type="date"],
+input[type="time"] {
+  overflow: hidden !important;
+}
diff --git a/toolkit/content/tests/browser/browser.ini b/toolkit/content/tests/browser/browser.ini
index 278b2ffe02..67ba2f850c 100644
--- a/toolkit/content/tests/browser/browser.ini
+++ b/toolkit/content/tests/browser/browser.ini
@@ -26,6 +26,7 @@ skip-if = !e10s
 [browser_contentTitle.js]
 [browser_crash_previous_frameloader.js]
 run-if = e10s && crashreporter
+[browser_datetime_datepicker.js]
 [browser_default_image_filename.js]
 [browser_f7_caret_browsing.js]
 [browser_findbar.js]
diff --git a/toolkit/content/tests/browser/browser_datetime_datepicker.js b/toolkit/content/tests/browser/browser_datetime_datepicker.js
new file mode 100644
index 0000000000..a0db761b7a
--- /dev/null
+++ b/toolkit/content/tests/browser/browser_datetime_datepicker.js
@@ -0,0 +1,222 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+const MONTH_YEAR = ".month-year",
+      DAYS_VIEW = ".days-view",
+      BTN_PREV_MONTH = ".prev",
+      BTN_NEXT_MONTH = ".next";
+const DATE_FORMAT = new Intl.DateTimeFormat("en-US", { year: "numeric", month: "long", timeZone: "UTC" }).format;
+
+// Create a list of abbreviations for calendar class names
+const W = "weekend",
+      O = "outside",
+      S = "selection",
+      R = "out-of-range",
+      T = "today",
+      P = "off-step";
+
+// Calendar classlist for 2016-12. Used to verify the classNames are correct.
+const calendarClasslist_201612 = [
+  [W, O], [O], [O], [O], [],  [],  [W],
+  [W],    [],  [],  [],  [],  [],  [W],
+  [W],    [],  [],  [],  [S], [],  [W],
+  [W],    [],  [],  [],  [],  [],  [W],
+  [W],    [],  [],  [],  [],  [],  [W],
+  [W, O], [O], [O], [O], [O], [O], [W, O],
+];
+
+function getCalendarText() {
+  return helper.getChildren(DAYS_VIEW).map(child => child.textContent);
+}
+
+function getCalendarClassList() {
+  return helper.getChildren(DAYS_VIEW).map(child => Array.from(child.classList));
+}
+
+function mergeArrays(a, b) {
+  return a.map((classlist, index) => classlist.concat(b[index]));
+}
+
+let helper = new DateTimeTestHelper();
+
+registerCleanupFunction(() => {
+  helper.cleanup();
+});
+
+/**
+ * Test that date picker opens to today's date when input field is blank
+ */
+add_task(async function test_datepicker_today() {
+  const date = new Date();
+
+  await helper.openPicker("data:text/html, <input type='date'>");
+
+  Assert.equal(helper.getElement(MONTH_YEAR).textContent, DATE_FORMAT(date));
+
+  await helper.tearDown();
+});
+
+/**
+ * Test that date picker opens to the correct month, with calendar days
+ * displayed correctly, given a date value is set.
+ */
+add_task(async function test_datepicker_open() {
+  const inputValue = "2016-12-15";
+
+  await helper.openPicker(`data:text/html, <input type="date" value="${inputValue}">`);
+
+  Assert.equal(helper.getElement(MONTH_YEAR).textContent, DATE_FORMAT(new Date(inputValue)));
+  Assert.deepEqual(
+    getCalendarText(),
+    [
+      "27", "28", "29", "30",  "1",  "2",  "3",
+       "4",  "5",  "6",  "7",  "8",  "9", "10",
+      "11", "12", "13", "14", "15", "16", "17",
+      "18", "19", "20", "21", "22", "23", "24",
+      "25", "26", "27", "28", "29", "30", "31",
+       "1",  "2",  "3",  "4",  "5",  "6",  "7",
+    ],
+    "2016-12",
+  );
+  Assert.deepEqual(
+    getCalendarClassList(),
+    calendarClasslist_201612,
+    "2016-12 classNames"
+  );
+
+  await helper.tearDown();
+});
+
+/**
+ * When the prev month button is clicked, calendar should display the dates for
+ * the previous month.
+ */
+add_task(async function test_datepicker_prev_month_btn() {
+  const inputValue = "2016-12-15";
+  const prevMonth = "2016-11-01";
+
+  await helper.openPicker(`data:text/html, <input type="date" value="${inputValue}">`);
+  helper.click(helper.getElement(BTN_PREV_MONTH));
+
+  Assert.equal(helper.getElement(MONTH_YEAR).textContent, DATE_FORMAT(new Date(prevMonth)));
+  Assert.deepEqual(
+    getCalendarText(),
+    [
+      "30", "31",  "1",  "2",  "3",  "4",  "5",
+       "6",  "7",  "8",  "9", "10", "11", "12",
+      "13", "14", "15", "16", "17", "18", "19",
+      "20", "21", "22", "23", "24", "25", "26",
+      "27", "28", "29", "30",  "1",  "2",  "3",
+       "4",  "5",  "6",  "7",  "8",  "9", "10",
+    ],
+    "2016-11",
+  );
+
+  await helper.tearDown();
+});
+
+/**
+ * When the next month button is clicked, calendar should display the dates for
+ * the next month.
+ */
+add_task(async function test_datepicker_next_month_btn() {
+  const inputValue = "2016-12-15";
+  const nextMonth = "2017-01-01";
+
+  await helper.openPicker(`data:text/html, <input type="date" value="${inputValue}">`);
+  helper.click(helper.getElement(BTN_NEXT_MONTH));
+
+  Assert.equal(helper.getElement(MONTH_YEAR).textContent, DATE_FORMAT(new Date(nextMonth)));
+  Assert.deepEqual(
+    getCalendarText(),
+    [
+      "25", "26", "27", "28", "29", "30", "31",
+       "1",  "2",  "3",  "4",  "5",  "6",  "7",
+       "8",  "9", "10", "11", "12", "13", "14",
+      "15", "16", "17", "18", "19", "20", "21",
+      "22", "23", "24", "25", "26", "27", "28",
+      "29", "30", "31",  "1",  "2",  "3",  "4",
+    ],
+    "2017-01",
+  );
+
+  await helper.tearDown();
+});
+
+/**
+ * When a date on the calendar is clicked, date picker should close and set
+ * value to the input box.
+ */
+add_task(async function test_datepicker_clicked() {
+  const inputValue = "2016-12-15";
+  const firstDayOnCalendar = "2016-11-27";
+
+  await helper.openPicker(`data:text/html, <input type="date" value="${inputValue}">`);
+  // Click the first item (top-left corner) of the calendar
+  helper.click(helper.getElement(DAYS_VIEW).children[0]);
+  await ContentTask.spawn(helper.tab.linkedBrowser, {}, async function() {
+    let inputEl = content.document.querySelector("input");
+    await ContentTaskUtils.waitForEvent(inputEl, "input");
+  });
+
+  Assert.equal(content.document.querySelector("input").value, firstDayOnCalendar);
+
+  await helper.tearDown();
+});
+
+/**
+ * When min and max attributes are set, calendar should show some dates as
+ * out-of-range.
+ */
+add_task(async function test_datepicker_min_max() {
+  const inputValue = "2016-12-15";
+  const inputMin = "2016-12-05";
+  const inputMax = "2016-12-25";
+
+  await helper.openPicker(`data:text/html, <input type="date" value="${inputValue}" min="${inputMin}" max="${inputMax}">`);
+
+  Assert.deepEqual(
+    getCalendarClassList(),
+    mergeArrays(calendarClasslist_201612, [
+      // R denotes out-of-range
+      [R], [R], [R], [R], [R], [R], [R],
+      [R], [],  [],  [],  [],  [],  [],
+      [],  [],  [],  [],  [],  [],  [],
+      [],  [],  [],  [],  [],  [],  [],
+      [],  [R], [R], [R], [R], [R], [R],
+      [R], [R], [R], [R], [R], [R], [R],
+    ]),
+    "2016-12 with min & max",
+  );
+
+  await helper.tearDown();
+});
+
+/**
+ * When step attribute is set, calendar should show some dates as off-step.
+ */
+add_task(async function test_datepicker_step() {
+  const inputValue = "2016-12-15";
+  const inputStep = "5";
+
+  await helper.openPicker(`data:text/html, <input type="date" value="${inputValue}" step="${inputStep}">`);
+
+  Assert.deepEqual(
+    getCalendarClassList(),
+    mergeArrays(calendarClasslist_201612, [
+      // P denotes off-step
+      [P], [P], [P], [],  [P], [P], [P],
+      [P], [],  [P], [P], [P], [P], [],
+      [P], [P], [P], [P], [],  [P], [P],
+      [P], [P], [],  [P], [P], [P], [P],
+      [],  [P], [P], [P], [P], [],  [P],
+      [P], [P], [P], [],  [P], [P], [P],
+    ]),
+    "2016-12 with step",
+  );
+
+  await helper.tearDown();
+});
diff --git a/toolkit/content/tests/browser/head.js b/toolkit/content/tests/browser/head.js
index 1c6c2b54f7..e3ef195382 100644
--- a/toolkit/content/tests/browser/head.js
+++ b/toolkit/content/tests/browser/head.js
@@ -31,3 +31,88 @@ function pushPrefs(...aPrefs) {
   SpecialPowers.pushPrefEnv({"set": aPrefs}, deferred.resolve);
   return deferred.promise;
 }
+
+/**
+ * Helper class for testing datetime input picker widget
+ */
+class DateTimeTestHelper {
+  constructor() {
+    this.panel = document.getElementById("DateTimePickerPanel");
+    this.panel.setAttribute("animate", false);
+    this.tab = null;
+    this.frame = null;
+  }
+
+  /**
+   * Opens a new tab with the URL of the test page, and make sure the picker is
+   * ready for testing.
+   *
+   * @param  {String} pageUrl
+   */
+  async openPicker(pageUrl) {
+    this.tab = await BrowserTestUtils.openNewForegroundTab(gBrowser, pageUrl);
+    await BrowserTestUtils.synthesizeMouseAtCenter("input", {}, gBrowser.selectedBrowser);
+    // If dateTimePopupFrame doesn't exist yet, wait for the binding to be attached
+    if (!this.panel.dateTimePopupFrame) {
+      await BrowserTestUtils.waitForEvent(this.panel, "DateTimePickerBindingReady")
+    }
+    this.frame = this.panel.dateTimePopupFrame;
+    await BrowserTestUtils.waitForEvent(this.frame, "load", true);
+    // Wait for picker elements to be ready and open panel transition to end
+    await BrowserTestUtils.waitForEvent(this.frame.contentDocument, "PickerReady");
+  }
+
+  /**
+   * Find an element on the picker.
+   *
+   * @param  {String} selector
+   * @return {DOMElement}
+   */
+  getElement(selector) {
+    return this.frame.contentDocument.querySelector(selector);
+  }
+
+  /**
+   * Find the children of an element on the picker.
+   *
+   * @param  {String} selector
+   * @return {Array<DOMElement>}
+   */
+  getChildren(selector) {
+    return Array.from(this.getElement(selector).children);
+  }
+
+  /**
+   * Click on an element
+   *
+   * @param  {DOMElement} element
+   */
+  click(element) {
+    EventUtils.synthesizeMouseAtCenter(element, {}, this.frame.contentWindow);
+  }
+
+  /**
+   * Close the panel and the tab
+   */
+  async tearDown() {
+    if (!this.panel.hidden) {
+      let pickerClosePromise = new Promise(resolve => {
+        this.panel.addEventListener("popuphidden", resolve, {once: true});
+      });
+      this.panel.closePicker();
+      await pickerClosePromise;
+    }
+    await BrowserTestUtils.removeTab(this.tab);
+    this.tab = null;
+  }
+
+  /**
+   * Clean up after tests. Remove the frame to prevent leak.
+   */
+  cleanup() {
+    this.frame.remove();
+    this.frame = null;
+    this.panel.removeAttribute("animate");
+    this.panel = null;
+  }
+}
diff --git a/toolkit/content/widgets/calendar.js b/toolkit/content/widgets/calendar.js
index 72e0d9d610..80c2976e08 100644
--- a/toolkit/content/widgets/calendar.js
+++ b/toolkit/content/widgets/calendar.js
@@ -54,23 +54,21 @@ function Calendar(options, context) {
      *          {
      *            {Number} textContent
      *            {Array<String>} classNames
+     *            {Boolean} enabled
      *          }
      *          {Function} getDayString: Transform day number to string
      *          {Function} getWeekHeaderString: Transform day of week number to string
-     *          {Function} setValue: Set value for dateKeeper
-     *          {Number} selectionValue: The selection date value
+     *          {Function} setSelection: Set selection for dateKeeper
      *        }
      */
     setProps(props) {
       if (props.isVisible) {
         // Transform the days and weekHeaders array for rendering
-        const days = props.days.map(({ dateValue, textContent, classNames }) => {
+        const days = props.days.map(({ dateObj, classNames, enabled }) => {
           return {
-            dateValue,
-            textContent: props.getDayString(textContent),
-            className: dateValue == props.selectionValue ?
-                       classNames.concat("selection").join(" ") :
-                       classNames.join(" ")
+          textContent: props.getDayString(dateObj.getUTCDate()),
+          className: classNames.join(" "),
+          enabled
           };
         });
         const weekHeaders = props.weekHeaders.map(({ textContent, classNames }) => {
@@ -152,10 +150,10 @@ function Calendar(options, context) {
         case "click": {
           if (event.target.parentNode == this.context.daysView) {
             let targetId = event.target.dataset.id;
-            this.props.setValue({
-              selectionValue: this.props.days[targetId].dateValue,
-              dateValue: this.props.days[targetId].dateValue
-            });
+            let targetObj = this.props.days[targetId];
+            if (targetObj.enabled) {
+              this.props.setSelection(targetObj.dateObj);
+            }
           }
           break;
         }
diff --git a/toolkit/content/widgets/datekeeper.js b/toolkit/content/widgets/datekeeper.js
index de01fdadee..9777ee647a 100644
--- a/toolkit/content/widgets/datekeeper.js
+++ b/toolkit/content/widgets/datekeeper.js
@@ -6,41 +6,72 @@
 
 /**
  * DateKeeper keeps track of the date states.
- *
- * @param {Object} date parts
- *        {
- *          {Number} year
- *          {Number} month
- *          {Number} day
- *        }
- *        {Object} options
- *        {
- *          {Number} firstDayOfWeek [optional]
- *          {Array<Number>} weekends [optional]
- *          {Number} calViewSize [optional]
- *        }
  */
-function DateKeeper({ year, month, day }, { firstDayOfWeek = 0, weekends = [0], calViewSize = 42 }) {
-  this.state = {
-    firstDayOfWeek, weekends, calViewSize,
-    dateObj: new Date(0),
-    years: [],
-    months: [],
-    days: []
-  };
-  this.state.weekHeaders = this._getWeekHeaders(firstDayOfWeek);
-  this._update(year, month, day);
+function DateKeeper(props) {
+  this.init(props);
 }
 
 {
   const DAYS_IN_A_WEEK = 7,
         MONTHS_IN_A_YEAR = 12,
         YEAR_VIEW_SIZE = 200,
-        YEAR_BUFFER_SIZE = 10;
+        YEAR_BUFFER_SIZE = 10,
+        // The min and max values are derived from the ECMAScript spec:
+        // http://ecma-international.org/ecma-262/5.1/#sec-15.9.1.1
+        MIN_DATE = -8640000000000000,
+        MAX_DATE = 8640000000000000;
 
   DateKeeper.prototype = {
+    get year() {
+      return this.state.dateObj.getUTCFullYear();
+    },
+
+    get month() {
+      return this.state.dateObj.getUTCMonth();
+    },
+
+    get day() {
+      return this.state.dateObj.getUTCDate();
+    },
+
+    get selection() {
+      return this.state.selection;
+    },
+
     /**
-     * Set new date
+     * Initialize DateKeeper
+     * @param  {Number} year
+     * @param  {Number} month
+     * @param  {Number} day
+     * @param  {String} min
+     * @param  {String} max
+     * @param  {Number} firstDayOfWeek
+     * @param  {Array<Number>} weekends
+     * @param  {Number} calViewSize
+     */
+    init({ year, month, day, min, max, firstDayOfWeek = 0, weekends = [0], calViewSize = 42 }) {
+      const today = new Date();
+      const isDateSet = year != undefined && month != undefined && day != undefined;
+
+      this.state = {
+        firstDayOfWeek, weekends, calViewSize,
+        min: new Date(min != undefined ? min : MIN_DATE),
+        max: new Date(max != undefined ? max : MAX_DATE),
+        today: this._newUTCDate(today.getFullYear(), today.getMonth(), today.getDate()),
+        weekHeaders: this._getWeekHeaders(firstDayOfWeek, weekends),
+        years: [],
+        months: [],
+        days: [],
+        selection: { year, month, day },
+      };
+
+      this.state.dateObj = isDateSet ?
+                           this._newUTCDate(year, month, day) :
+                           new Date(this.state.today);
+    },
+    /**
+     * Set new date. The year is always treated as full year, so the short-form
+     * is not supported.
      * @param {Object} date parts
      *        {
      *          {Number} year [optional]
@@ -48,17 +79,21 @@ function DateKeeper({ year, month, day }, { firstDayOfWeek = 0, weekends = [0],
      *          {Number} date [optional]
      *        }
      */
-    set({ year = this.state.year, month = this.state.month, day = this.state.day }) {
-      this._update(year, month, day);
+    set({ year = this.year, month = this.month, day = this.day }) {
+      // Use setUTCFullYear so that year 99 doesn't get parsed as 1999
+      this.state.dateObj.setUTCFullYear(year, month, day);
     },
 
     /**
-     * Set date with value
-     * @param {Number} value: Date value
+     * Set selection date
+     * @param {Number} year
+     * @param {Number} month
+     * @param {Number} day
      */
-    setValue(value) {
-      const dateObj = new Date(value);
-      this._update(dateObj.getUTCFullYear(), dateObj.getUTCMonth(), dateObj.getUTCDate());
+    setSelection({ year, month, day }) {
+      this.state.selection.year = year;
+      this.state.selection.month = month;
+      this.state.selection.day = day;
     },
 
     /**
@@ -66,8 +101,10 @@ function DateKeeper({ year, month, day }, { firstDayOfWeek = 0, weekends = [0],
      * @param {Number} month
      */
     setMonth(month) {
-      const lastDayOfMonth = this._newUTCDate(this.state.year, month + 1, 0).getUTCDate();
-      this._update(this.state.year, month, Math.min(this.state.day, lastDayOfMonth));
+      const lastDayOfMonth = this._newUTCDate(this.year, month + 1, 0).getUTCDate();
+      this.set({ year: this.year,
+                 month,
+                 day: Math.min(this.day, lastDayOfMonth) });
     },
 
     /**
@@ -75,8 +112,10 @@ function DateKeeper({ year, month, day }, { firstDayOfWeek = 0, weekends = [0],
      * @param {Number} year
      */
     setYear(year) {
-      const lastDayOfMonth = this._newUTCDate(year, this.state.month + 1, 0).getUTCDate();
-      this._update(year, this.state.month, Math.min(this.state.day, lastDayOfMonth));
+      const lastDayOfMonth = this._newUTCDate(year, this.month + 1, 0).getUTCDate();
+      this.set({ year,
+                 month: this.month,
+                 day: Math.min(this.day, lastDayOfMonth) });
     },
 
     /**
@@ -84,22 +123,10 @@ function DateKeeper({ year, month, day }, { firstDayOfWeek = 0, weekends = [0],
      * @param {Number} offset
      */
     setMonthByOffset(offset) {
-      const lastDayOfMonth = this._newUTCDate(this.state.year, this.state.month + offset + 1, 0).getUTCDate();
-      this._update(this.state.year, this.state.month + offset, Math.min(this.state.day, lastDayOfMonth));
-    },
-
-    /**
-     * Update the states.
-     * @param  {Number} year  [description]
-     * @param  {Number} month [description]
-     * @param  {Number} day  [description]
-     */
-    _update(year, month, day) {
-      // Use setUTCFullYear so that year 99 doesn't get parsed as 1999
-      this.state.dateObj.setUTCFullYear(year, month, day);
-      this.state.year = this.state.dateObj.getUTCFullYear();
-      this.state.month = this.state.dateObj.getUTCMonth();
-      this.state.day = this.state.dateObj.getUTCDate();
+      const lastDayOfMonth = this._newUTCDate(this.year, this.month + offset + 1, 0).getUTCDate();
+      this.set({ year: this.year,
+                 month: this.month + offset,
+                 day: Math.min(this.day, lastDayOfMonth) });
     },
 
     /**
@@ -111,7 +138,6 @@ function DateKeeper({ year, month, day }, { firstDayOfWeek = 0, weekends = [0],
      *         }
      */
     getMonths() {
-      // TODO: add min/max and step support
       let months = [];
 
       for (let i = 0; i < MONTHS_IN_A_YEAR; i++) {
@@ -133,12 +159,11 @@ function DateKeeper({ year, month, day }, { firstDayOfWeek = 0, weekends = [0],
      *         }
      */
     getYears() {
-      // TODO: add min/max and step support
       let years = [];
 
       const firstItem = this.state.years[0];
       const lastItem = this.state.years[this.state.years.length - 1];
-      const currentYear = this.state.dateObj.getUTCFullYear();
+      const currentYear = this.year;
 
       // Generate new years array when the year is outside of the first &
       // last item range. If not, return the cached result.
@@ -161,30 +186,43 @@ function DateKeeper({ year, month, day }, { firstDayOfWeek = 0, weekends = [0],
      * Get days for calendar
      * @return {Array<Object>}
      *         {
-     *           {Number} dateValue
-     *           {Number} textContent
+     *           {Date} dateObj
      *           {Array<String>} classNames
+     *           {Boolean} enabled
      *         }
      */
     getDays() {
-      // TODO: add min/max and step support
-      let firstDayOfMonth = this._getFirstCalendarDate(this.state.dateObj, this.state.firstDayOfWeek);
+      // TODO: add step support
+      const firstDayOfMonth = this._getFirstCalendarDate(this.state.dateObj, this.state.firstDayOfWeek);
+      const month = this.month;
       let days = [];
-      let month = this.state.dateObj.getUTCMonth();
 
       for (let i = 0; i < this.state.calViewSize; i++) {
-        let dateObj = this._newUTCDate(firstDayOfMonth.getUTCFullYear(), firstDayOfMonth.getUTCMonth(), firstDayOfMonth.getUTCDate() + i);
+        const dateObj = this._newUTCDate(firstDayOfMonth.getUTCFullYear(), firstDayOfMonth.getUTCMonth(), firstDayOfMonth.getUTCDate() + i);
         let classNames = [];
+        let enabled = true;
         if (this.state.weekends.includes(dateObj.getUTCDay())) {
           classNames.push("weekend");
         }
         if (month != dateObj.getUTCMonth()) {
           classNames.push("outside");
         }
+        if (this.state.selection.year == dateObj.getUTCFullYear() &&
+            this.state.selection.month == dateObj.getUTCMonth() &&
+            this.state.selection.day == dateObj.getUTCDate()) {
+          classNames.push("selection");
+        }
+        if (dateObj.getTime() < this.state.min.getTime() || dateObj.getTime() > this.state.max.getTime()) {
+          classNames.push("out-of-range");
+          enabled = false;
+        }
+        if (this.state.today.getTime() == dateObj.getTime()) {
+          classNames.push("today");
+        }
         days.push({
-          dateValue: dateObj.getTime(),
-          textContent: dateObj.getUTCDate(),
-          classNames
+          dateObj,
+          classNames,
+          enabled,
         });
       }
       return days;
@@ -193,20 +231,21 @@ function DateKeeper({ year, month, day }, { firstDayOfWeek = 0, weekends = [0],
     /**
      * Get week headers for calendar
      * @param  {Number} firstDayOfWeek
+     * @param  {Array<Number>} weekends
      * @return {Array<Object>}
      *         {
      *           {Number} textContent
      *           {Array<String>} classNames
      *         }
      */
-    _getWeekHeaders(firstDayOfWeek) {
+    _getWeekHeaders(firstDayOfWeek, weekends) {
       let headers = [];
       let dayOfWeek = firstDayOfWeek;
 
       for (let i = 0; i < DAYS_IN_A_WEEK; i++) {
         headers.push({
           textContent: dayOfWeek % DAYS_IN_A_WEEK,
-          classNames: this.state.weekends.includes(dayOfWeek % DAYS_IN_A_WEEK) ? ["weekend"] : []
+          classNames: weekends.includes(dayOfWeek % DAYS_IN_A_WEEK) ? ["weekend"] : []
         });
         dayOfWeek++;
       }
diff --git a/toolkit/content/widgets/datepicker.js b/toolkit/content/widgets/datepicker.js
index 210ca856cf..317f0ae94c 100644
--- a/toolkit/content/widgets/datepicker.js
+++ b/toolkit/content/widgets/datepicker.js
@@ -20,6 +20,12 @@ function DatePicker(context) {
      *           {Number} year [optional]
      *           {Number} month [optional]
      *           {Number} date [optional]
+     *           {String} min
+     *           {String} max
+     *           {Number} firstDayOfWeek
+     *           {Array<Number>} weekends
+     *           {Array<String>} monthStrings
+     *           {Array<String>} weekdayStrings
      *           {String} locale [optional]: User preferred locale
      *         }
      */
@@ -28,57 +34,54 @@ function DatePicker(context) {
       this._setDefaultState();
       this._createComponents();
       this._update();
+      document.dispatchEvent(new CustomEvent("PickerReady"));
     },
 
     /*
      * Set initial date picker states.
      */
     _setDefaultState() {
-      const now = new Date();
-      const { year = now.getFullYear(),
-              month = now.getMonth(),
-              day = now.getDate(),
-              locale } = this.props;
-
-      // TODO: Use calendar info API to get first day of week & weekends
-      //       (Bug 1287503)
+      const { year, month, day, min, max, firstDayOfWeek, weekends,
+              monthStrings, weekdayStrings, locale } = this.props;
       const dateKeeper = new DateKeeper({
-        year, month, day
-      }, {
-        calViewSize: CAL_VIEW_SIZE,
-        firstDayOfWeek: 0,
-        weekends: [0]
+        year, month, day, min, max, firstDayOfWeek, weekends,
+        calViewSize: CAL_VIEW_SIZE
       });
 
       this.state = {
         dateKeeper,
         locale,
         isMonthPickerVisible: false,
-        isYearSet: false,
-        isMonthSet: false,
-        isDateSet: false,
         getDayString: new Intl.NumberFormat(locale).format,
-        // TODO: use calendar terms when available (Bug 1287677)
-        getWeekHeaderString: weekday => ["Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"][weekday],
-        setValue: ({ dateValue, selectionValue }) => {
-          dateKeeper.setValue(dateValue);
-          this.state.selectionValue = selectionValue;
-          this.state.isYearSet = true;
-          this.state.isMonthSet = true;
-          this.state.isDateSet = true;
+        getWeekHeaderString: weekday => weekdayStrings[weekday],
+        getMonthString: month => monthStrings[month],
+        setSelection: date => {
+          dateKeeper.setSelection({
+            year: date.getUTCFullYear(),
+            month: date.getUTCMonth(),
+            day: date.getUTCDate(),
+          });
           this._update();
           this._dispatchState();
           this._closePopup();
         },
         setYear: year => {
           dateKeeper.setYear(year);
-          this.state.isYearSet = true;
+          dateKeeper.setSelection({
+            year,
+            month: dateKeeper.selection.month,
+            day: dateKeeper.selection.day,
+          });
           this._update();
           this._dispatchState();
         },
         setMonth: month => {
           dateKeeper.setMonth(month);
-          this.state.isMonthSet = true;
+          dateKeeper.setSelection({
+            year: dateKeeper.selection.year,
+            month,
+            day: dateKeeper.selection.day,
+          });
           this._update();
           this._dispatchState();
         },
@@ -104,6 +107,7 @@ function DatePicker(context) {
         monthYear: new MonthYear({
           setYear: this.state.setYear,
           setMonth: this.state.setMonth,
+          getMonthString: this.state.getMonthString,
           locale: this.state.locale
         }, {
           monthYear: this.context.monthYear,
@@ -116,7 +120,7 @@ function DatePicker(context) {
      * Update date picker and its components.
      */
     _update() {
-      const { dateKeeper, selectionValue, isMonthPickerVisible } = this.state;
+      const { dateKeeper, isMonthPickerVisible } = this.state;
 
       if (isMonthPickerVisible) {
         this.state.months = dateKeeper.getMonths();
@@ -128,9 +132,7 @@ function DatePicker(context) {
       this.components.monthYear.setProps({
         isVisible: isMonthPickerVisible,
         dateObj: dateKeeper.state.dateObj,
-        month: dateKeeper.state.month,
         months: this.state.months,
-        year: dateKeeper.state.year,
         years: this.state.years,
         toggleMonthPicker: this.state.toggleMonthPicker
       });
@@ -138,10 +140,9 @@ function DatePicker(context) {
         isVisible: !isMonthPickerVisible,
         days: this.state.days,
         weekHeaders: dateKeeper.state.weekHeaders,
-        setValue: this.state.setValue,
+        setSelection: this.state.setSelection,
         getDayString: this.state.getDayString,
-        getWeekHeaderString: this.state.getWeekHeaderString,
-        selectionValue
+        getWeekHeaderString: this.state.getWeekHeaderString
       });
 
       isMonthPickerVisible ?
@@ -162,8 +163,7 @@ function DatePicker(context) {
      * Use postMessage to pass the state of picker to the panel.
      */
     _dispatchState() {
-      const { year, month, day } = this.state.dateKeeper.state;
-      const { isYearSet, isMonthSet, isDaySet } = this.state;
+      const { year, month, day } = this.state.dateKeeper.selection;
       // The panel is listening to window for postMessage event, so we
       // do postMessage to itself to send data to input boxes.
       window.postMessage({
@@ -172,9 +172,6 @@ function DatePicker(context) {
           year,
           month,
           day,
-          isYearSet,
-          isMonthSet,
-          isDaySet
         }
       }, "*");
     },
@@ -255,19 +252,12 @@ function DatePicker(context) {
     set({ year, month, day }) {
       const { dateKeeper } = this.state;
 
-      if (year != undefined) {
-        this.state.isYearSet = true;
-      }
-      if (month != undefined) {
-        this.state.isMonthSet = true;
-      }
-      if (day != undefined) {
-        this.state.isDaySet = true;
-      }
-
       dateKeeper.set({
         year, month, day
       });
+      dateKeeper.setSelection({
+        year, month, day
+      });
       this._update();
     }
   };
@@ -280,12 +270,12 @@ function DatePicker(context) {
    *          {String} locale
    *          {Function} setYear
    *          {Function} setMonth
+   *          {Function} getMonthString
    *        }
    * @param {DOMElement} context
    */
   function MonthYear(options, context) {
     const spinnerSize = 5;
-    const monthFormat = new Intl.DateTimeFormat(options.locale, { month: "short" }).format;
     const yearFormat = new Intl.DateTimeFormat(options.locale, { year: "numeric" }).format;
     const dateFormat = new Intl.DateTimeFormat(options.locale, { year: "numeric", month: "long" }).format;
 
@@ -298,7 +288,7 @@ function DatePicker(context) {
           this.state.isMonthSet = true;
           options.setMonth(month);
         },
-        getDisplayString: month => monthFormat(new Date(0, month)),
+        getDisplayString: options.getMonthString,
         viewportSize: spinnerSize
       }, context.monthYearView),
       year: new Spinner({
@@ -323,8 +313,6 @@ function DatePicker(context) {
      *        {
      *          {Boolean} isVisible
      *          {Date} dateObj
-     *          {Number} month
-     *          {Number} year
      *          {Array<Object>} months
      *          {Array<Object>} years
      *          {Function} toggleMonthPicker
@@ -336,14 +324,14 @@ function DatePicker(context) {
       if (props.isVisible) {
         this.context.monthYear.classList.add("active");
         this.components.month.setState({
-          value: props.month,
+          value: props.dateObj.getUTCMonth(),
           items: props.months,
           isInfiniteScroll: true,
           isValueSet: this.state.isMonthSet,
           smoothScroll: !this.state.firstOpened
         });
         this.components.year.setState({
-          value: props.year,
+          value: props.dateObj.getUTCFullYear(),
           items: props.years,
           isInfiniteScroll: false,
           isValueSet: this.state.isYearSet,
diff --git a/toolkit/content/widgets/datetimebox.css b/toolkit/content/widgets/datetimebox.css
index 18ff024c78..ce638078fa 100644
--- a/toolkit/content/widgets/datetimebox.css
+++ b/toolkit/content/widgets/datetimebox.css
@@ -8,9 +8,17 @@
 .datetime-input-box-wrapper {
   -moz-appearance: none;
   display: inline-flex;
+  flex: 1;
   cursor: default;
   background-color: inherit;
   color: inherit;
+  min-width: 0;
+  justify-content: space-between;
+}
+
+.datetime-input-edit-wrapper {
+  overflow: hidden;
+  white-space: nowrap;
 }
 
 .datetime-input {
@@ -43,5 +51,5 @@
   height: 12px;
   width: 12px;
   align-self: center;
-  justify-content: flex-end;
+  flex: none;
 }
diff --git a/toolkit/content/widgets/datetimebox.xml b/toolkit/content/widgets/datetimebox.xml
index 5859f80dd1..c276265a3d 100644
--- a/toolkit/content/widgets/datetimebox.xml
+++ b/toolkit/content/widgets/datetimebox.xml
@@ -4,6 +4,11 @@
    - License, v. 2.0. If a copy of the MPL was not distributed with this
    - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
 
+<!DOCTYPE bindings [
+<!ENTITY % datetimeboxDTD SYSTEM "chrome://global/locale/datetimebox.dtd">
+%datetimeboxDTD;
+]>
+
 <bindings id="datetimeboxBindings"
    xmlns="http://www.mozilla.org/xbl"
    xmlns:html="http://www.w3.org/1999/xhtml"
@@ -21,12 +26,13 @@
     <implementation>
       <constructor>
       <![CDATA[
-        // TODO: Bug 1320227 - [DateTimeInput] localization for
-        // <input type=date> input box
-        this.mMonthPlaceHolder = "mm";
-        this.mDayPlaceHolder = "dd";
-        this.mYearPlaceHolder = "yyyy";
+        /* eslint-disable no-multi-spaces */
+        this.mYearPlaceHolder = ]]>"&date.year.placeholder;"<![CDATA[;
+        this.mMonthPlaceHolder = ]]>"&date.month.placeholder;"<![CDATA[;
+        this.mDayPlaceHolder = ]]>"&date.day.placeholder;"<![CDATA[;
         this.mSeparatorText = "/";
+        /* eslint-enable no-multi-spaces */
+
         this.mMinMonth = 1;
         this.mMaxMonth = 12;
         this.mMinDay = 1;
@@ -76,6 +82,7 @@
         if (this.mInputElement.value) {
           this.setFieldsFromInputValue();
         }
+        this.updateResetButtonVisibility();
       ]]>
       </constructor>
 
@@ -107,9 +114,11 @@
             this.mYearField.setAttribute("typeBuffer", "");
           }
 
-          if (!aFromInputElement) {
+          if (!aFromInputElement && this.mInputElement.value) {
             this.mInputElement.setUserInput("");
           }
+
+          this.updateResetButtonVisibility();
         ]]>
         </body>
       </method>
@@ -170,6 +179,13 @@
       <method name="setInputValueFromFields">
         <body>
         <![CDATA[
+          if (!this.isAnyValueAvailable(false) && this.mInputElement.value) {
+            // Values in the input box was cleared, clear the input element's
+            // value if not empty.
+            this.mInputElement.setUserInput("");
+            return;
+          }
+
           if (this.isFieldInvalid(this.mYearField) ||
               this.isFieldInvalid(this.mMonthField) ||
               this.isFieldInvalid(this.mDayField)) {
@@ -192,6 +208,10 @@
 
           let date = [year, month, day].join("-");
 
+          if (date == this.mInputElement.value) {
+            return;
+          }
+
           this.log("setInputValueFromFields: " + date);
           this.mInputElement.setUserInput(date);
         ]]>
@@ -217,6 +237,9 @@
           if (!this.isEmpty(day)) {
             this.setFieldValue(this.mDayField, day);
           }
+
+          // Update input element's .value if needed.
+          this.setInputValueFromFields();
         ]]>
         </body>
       </method>
@@ -302,6 +325,12 @@
           let targetField = aEvent.originalTarget;
           let key = aEvent.key;
 
+          // Home/End key does nothing on year field.
+          if (targetField == this.mYearField && (key == "Home" ||
+                                                 key == "End")) {
+            return;
+          }
+
           switch (key) {
             case "ArrowUp":
               this.incrementFieldValue(targetField, 1);
@@ -406,11 +435,13 @@
           }
 
           aField.value = value;
+          this.updateResetButtonVisibility();
         ]]>
         </body>
       </method>
 
-      <method name="isValueAvailable">
+      <method name="isAnyValueAvailable">
+        <parameter name="aForPicker"/>
         <body>
         <![CDATA[
           return !this.isEmpty(this.mMonthField.value) ||
@@ -492,6 +523,7 @@
         if (this.mInputElement.value) {
           this.setFieldsFromInputValue();
         }
+        this.updateResetButtonVisibility();
         ]]>
       </constructor>
 
@@ -551,7 +583,7 @@
           }
 
           this.log("setFieldsFromInputValue: " + value);
-          let [hour, minute, second] = value.split(':');
+          let [hour, minute, second] = value.split(":");
 
           this.setFieldValue(this.mHourField, hour);
           this.setFieldValue(this.mMinuteField, minute);
@@ -617,6 +649,13 @@
       <method name="setInputValueFromFields">
         <body>
         <![CDATA[
+          if (!this.isAnyValueAvailable(false) && this.mInputElement.value) {
+            // Values in the input box was cleared, clear the input element's
+            // value if not empty.
+            this.mInputElement.setUserInput("");
+            return;
+          }
+
           if (this.isEmpty(this.mHourField.value) ||
               this.isEmpty(this.mMinuteField.value) ||
               (this.mDayPeriodField && this.isEmpty(this.mDayPeriodField.value)) ||
@@ -652,6 +691,10 @@
             time += "." + this.mMillisecField.value;
           }
 
+          if (time == this.mInputElement.value) {
+            return;
+          }
+
           this.log("setInputValueFromFields: " + time);
           this.mInputElement.setUserInput(time);
         ]]>
@@ -678,6 +721,9 @@
           if (!this.isEmpty(minute)) {
             this.setFieldValue(this.mMinuteField, minute);
           }
+
+          // Update input element's .value if needed.
+          this.setInputValueFromFields();
         ]]>
         </body>
        </method>
@@ -721,9 +767,11 @@
             this.mDayPeriodField.value = "";
           }
 
-          if (!aFromInputElement) {
+          if (!aFromInputElement && this.mInputElement.value) {
             this.mInputElement.setUserInput("");
           }
+
+          this.updateResetButtonVisibility();
         ]]>
         </body>
       </method>
@@ -793,6 +841,7 @@
               this.mDayPeriodField.value == this.mAMIndicator ?
                 this.mPMIndicator : this.mAMIndicator;
             this.mDayPeriodField.select();
+            this.updateResetButtonVisibility();
             this.setInputValueFromFields();
             return;
           }
@@ -850,6 +899,7 @@
               this.mDayPeriodField.value = this.mPMIndicator;
               this.mDayPeriodField.select();
             }
+            this.updateResetButtonVisibility();
             return;
           }
 
@@ -905,16 +955,30 @@
           }
 
           aField.value = value;
+          this.updateResetButtonVisibility();
         ]]>
         </body>
       </method>
 
-      <method name="isValueAvailable">
+      <method name="isAnyValueAvailable">
+        <parameter name="aForPicker"/>
         <body>
         <![CDATA[
+          let available = !this.isEmpty(this.mHourField.value) ||
+                          !this.isEmpty(this.mMinuteField.value);
+
+          if (available) {
+            return true;
+          }
+
           // Picker only cares about hour:minute.
-          return !this.isEmpty(this.mHourField.value) ||
-                 !this.isEmpty(this.mMinuteField.value);
+          if (aForPicker) {
+            return false;
+          }
+
+          return (this.mDayPeriodField && !this.isEmpty(this.mDayPeriodField.value)) ||
+                 (this.mSecondField && !this.isEmpty(this.mSecondField.value)) ||
+                 (this.mMillisecField && !this.isEmpty(this.mMillisecField.value));
         ]]>
         </body>
       </method>
@@ -963,7 +1027,8 @@
     <content>
       <html:div class="datetime-input-box-wrapper"
                 xbl:inherits="context,disabled,readonly">
-        <html:span>
+        <html:span class="datetime-input-edit-wrapper"
+                   anonid="edit-wrapper">
           <html:input anonid="input-one"
                       class="textbox-input datetime-input numeric"
                       size="2" maxlength="2"
@@ -980,9 +1045,8 @@
                       xbl:inherits="disabled,readonly,tabindex"/>
         </html:span>
 
-        <html:button class="datetime-reset-button" anoid="reset-button"
-                     tabindex="-1" xbl:inherits="disabled"
-                     onclick="document.getBindingParent(this).clearInputFields(false);"/>
+        <html:button class="datetime-reset-button" anonid="reset-button"
+                     tabindex="-1" xbl:inherits="disabled"/>
       </html:div>
     </content>
 
@@ -997,6 +1061,9 @@
         this.mStep = this.mInputElement.step;
         this.mIsPickerOpen = false;
 
+        this.mResetButton =
+          document.getAnonymousElementByAttribute(this, "anonid", "reset-button");
+
         this.EVENTS.forEach((eventName) => {
           this.addEventListener(eventName, this, { mozSystemGroup: true });
         });
@@ -1005,6 +1072,9 @@
           capture: true,
           mozSystemGroup: true
         });
+        // This is to close the picker when input element blurs.
+        this.mInputElement.addEventListener("blur", this,
+                                            { mozSystemGroup: true });
       ]]>
       </constructor>
 
@@ -1025,7 +1095,7 @@
       <property name="EVENTS" readonly="true">
         <getter>
         <![CDATA[
-          return ["click", "focus", "blur", "copy", "cut", "paste"];
+          return ["click", "focus", "blur", "copy", "cut", "paste", "mousedown"];
         ]]>
         </getter>
       </property>
@@ -1041,6 +1111,18 @@
         </body>
       </method>
 
+      <method name="updateResetButtonVisibility">
+        <body>
+          <![CDATA[
+            if (this.isAnyValueAvailable(false)) {
+              this.mResetButton.style.visibility = "visible";
+            } else {
+              this.mResetButton.style.visibility = "hidden";
+            }
+          ]]>
+        </body>
+      </method>
+
       <method name="focusInnerTextBox">
         <body>
         <![CDATA[
@@ -1164,10 +1246,16 @@
         </body>
       </method>
 
+      <method name="isAnyValueAvailable">
+        <body>
+          throw Components.results.NS_ERROR_NOT_IMPLEMENTED;
+        </body>
+      </method>
+
       <method name="notifyPicker">
         <body>
         <![CDATA[
-          if (this.mIsPickerOpen && this.isValueAvailable()) {
+          if (this.mIsPickerOpen && this.isAnyValueAvailable(true)) {
             this.mInputElement.updateDateTimePicker(this.getCurrentValue());
           }
         ]]>
@@ -1213,6 +1301,12 @@
               this.onBlur(aEvent);
               break;
             }
+            case "mousedown": {
+              if (aEvent.originalTarget == this.mResetButton) {
+                aEvent.preventDefault();
+              }
+              break;
+            }
             case "copy":
             case "cut":
             case "paste": {
@@ -1245,7 +1339,12 @@
         <parameter name="aEvent"/>
         <body>
         <![CDATA[
-          this.log("onBlur originalTarget: " + aEvent.originalTarget);
+          this.log("onBlur originalTarget: " + aEvent.originalTarget +
+            " target: " + aEvent.target);
+
+          if (aEvent.target == this.mInputElement && this.mIsPickerOpen) {
+            this.mInputElement.closeDateTimePicker();
+          }
 
           let target = aEvent.originalTarget;
           target.setAttribute("typeBuffer", "");
@@ -1261,16 +1360,23 @@
           this.log("onKeyPress key: " + aEvent.key);
 
           switch (aEvent.key) {
-            // Close picker on Enter or Space key.
+            // Close picker on Enter, Escape or Space key.
             case "Enter":
+            case "Escape":
             case " ": {
-              this.mInputElement.closeDateTimePicker();
-              aEvent.preventDefault();
+              if (this.mIsPickerOpen) {
+                this.mInputElement.closeDateTimePicker();
+                aEvent.preventDefault();
+              }
               break;
             }
             case "Backspace": {
               let targetField = aEvent.originalTarget;
+              targetField.value = "";
               targetField.setAttribute("typeBuffer", "");
+              this.updateResetButtonVisibility();
+              this.setInputValueFromFields();
+              aEvent.preventDefault();
               break;
             }
             case "ArrowRight":
@@ -1312,12 +1418,14 @@
           // XXX: .originalTarget is not expected.
           // When clicking on one of the inner text boxes, the .originalTarget is
           // a HTMLDivElement and when clicking on the reset button, it's a
-          // HTMLButtonElement but it's not equal to our reset-button.
+          // HTMLButtonElement.
           if (aEvent.defaultPrevented || this.isDisabled() || this.isReadonly()) {
             return;
           }
 
-          if (!(aEvent.originalTarget instanceof HTMLButtonElement)) {
+          if (aEvent.originalTarget == this.mResetButton) {
+            this.clearInputFields(false);
+          } else if (!this.mIsPickerOpen) {
             this.mInputElement.openDateTimePicker(this.getCurrentValue());
           }
         ]]>
diff --git a/toolkit/content/widgets/datetimepicker.xml b/toolkit/content/widgets/datetimepicker.xml
index 5f16f1ff0c..1d6a5e7722 100644
--- a/toolkit/content/widgets/datetimepicker.xml
+++ b/toolkit/content/widgets/datetimepicker.xml
@@ -999,13 +999,13 @@
         <body>
           <![CDATA[
             var locale = Intl.DateTimeFormat().resolvedOptions().locale + "-u-ca-gregory";
-            var dtfMonth = Intl.DateTimeFormat(locale, {month: "long"});
+            var dtfMonth = Intl.DateTimeFormat(locale, {month: "long", timeZone: "UTC"});
             var dtfWeekday = Intl.DateTimeFormat(locale, {weekday: "narrow"});
 
             var monthLabel = this.monthField.firstChild;
-            var tempDate = new Date(2005, 0, 1);
+            var tempDate = new Date(Date.UTC(2005, 0, 1));
             for (var month = 0; month < 12; month++) {
-              tempDate.setMonth(month);
+              tempDate.setUTCMonth(month);
               monthLabel.setAttribute("value", dtfMonth.format(tempDate));
               monthLabel = monthLabel.nextSibling;
             }
diff --git a/toolkit/content/widgets/datetimepopup.xml b/toolkit/content/widgets/datetimepopup.xml
index 86e8780c15..52df7de750 100644
--- a/toolkit/content/widgets/datetimepopup.xml
+++ b/toolkit/content/widgets/datetimepopup.xml
@@ -22,11 +22,20 @@
       <field name="TIME_PICKER_HEIGHT" readonly="true">"21em"</field>
       <field name="DATE_PICKER_WIDTH" readonly="true">"23.1em"</field>
       <field name="DATE_PICKER_HEIGHT" readonly="true">"20.7em"</field>
-      <method name="loadPicker">
+      <constructor><![CDATA[
+        this.l10n = {};
+        const mozIntl = Components.classes["@mozilla.org/mozintl;1"]
+                          .getService(Components.interfaces.mozIMozIntl);
+        mozIntl.addGetCalendarInfo(l10n);
+        mozIntl.addGetDisplayNames(l10n);
+        // Notify DateTimePickerHelper.jsm that binding is ready.
+        this.dispatchEvent(new CustomEvent("DateTimePickerBindingReady"));
+      ]]></constructor>
+      <method name="openPicker">
         <parameter name="type"/>
+        <parameter name="anchor"/>
         <parameter name="detail"/>
         <body><![CDATA[
-          this.hidden = false;
           this.type = type;
           this.pickerState = {};
           // TODO: Resize picker according to content zoom level
@@ -49,17 +58,20 @@
               break;
             }
           }
+          this.hidden = false;
+          this.openPopup(anchor, "after_start", 0, 0);
         ]]></body>
       </method>
       <method name="closePicker">
         <body><![CDATA[
-          this.hidden = true;
           this.setInputBoxValue(true);
           this.pickerState = {};
           this.type = undefined;
           this.dateTimePopupFrame.removeEventListener("load", this, true);
           this.dateTimePopupFrame.contentDocument.removeEventListener("message", this, false);
           this.dateTimePopupFrame.setAttribute("src", "");
+          this.hidePopup();
+          this.hidden = true;
         ]]></body>
       </method>
       <method name="setPopupValue">
@@ -115,6 +127,34 @@
             }
             case "date": {
               const { year, month, day } = detail.value;
+              const { firstDayOfWeek, weekends } =
+                this.getCalendarInfo(locale);
+              const monthStrings = this.getDisplayNames(
+                locale, [
+                  "dates/gregorian/months/january",
+                  "dates/gregorian/months/february",
+                  "dates/gregorian/months/march",
+                  "dates/gregorian/months/april",
+                  "dates/gregorian/months/may",
+                  "dates/gregorian/months/june",
+                  "dates/gregorian/months/july",
+                  "dates/gregorian/months/august",
+                  "dates/gregorian/months/september",
+                  "dates/gregorian/months/october",
+                  "dates/gregorian/months/november",
+                  "dates/gregorian/months/december",
+                ], "short");
+              const weekdayStrings = this.getDisplayNames(
+                locale, [
+                  "dates/gregorian/weekdays/sunday",
+                  "dates/gregorian/weekdays/monday",
+                  "dates/gregorian/weekdays/tuesday",
+                  "dates/gregorian/weekdays/wednesday",
+                  "dates/gregorian/weekdays/thursday",
+                  "dates/gregorian/weekdays/friday",
+                  "dates/gregorian/weekdays/saturday",
+                ], "short");
+
               this.postMessageToPicker({
                 name: "PickerInit",
                 detail: {
@@ -122,7 +162,13 @@
                   // Month value from input box starts from 1 instead of 0
                   month: month == undefined ? undefined : month - 1,
                   day,
-                  locale
+                  firstDayOfWeek,
+                  weekends,
+                  monthStrings,
+                  weekdayStrings,
+                  locale,
+                  min: detail.min,
+                  max: detail.max,
                 }
               });
               break;
@@ -184,6 +230,46 @@
           }
         ]]></body>
       </method>
+      <method name="getCalendarInfo">
+        <parameter name="locale"/>
+        <body><![CDATA[
+          const calendarInfo = this.l10n.getCalendarInfo(locale);
+
+          // Day of week from calendarInfo starts from 1 as Sunday to 7 as Saturday,
+          // so they need to be mapped to JavaScript convention with 0 as Sunday
+          // and 6 as Saturday
+          let firstDayOfWeek = calendarInfo.firstDayOfWeek - 1,
+              weekendStart = calendarInfo.weekendStart - 1,
+              weekendEnd = calendarInfo.weekendEnd - 1;
+
+          let weekends = [];
+
+          // Make sure weekendEnd is greater than weekendStart
+          if (weekendEnd < weekendStart) {
+            weekendEnd += 7;
+          }
+
+          // We get the weekends by incrementing weekendStart up to weekendEnd.
+          // If the start and end is the same day, then weekends only has one day.
+          for (let day = weekendStart; day <= weekendEnd; day++) {
+            weekends.push(day % 7);
+          }
+
+          return {
+            firstDayOfWeek,
+            weekends
+          }
+        ]]></body>
+      </method>
+      <method name="getDisplayNames">
+        <parameter name="locale"/>
+        <parameter name="keys"/>
+        <parameter name="style"/>
+        <body><![CDATA[
+          const displayNames = this.l10n.getDisplayNames(locale, {keys, style});
+          return keys.map(key => displayNames.values[key]);
+        ]]></body>
+      </method>
       <method name="handleEvent">
         <parameter name="aEvent"/>
         <body><![CDATA[
@@ -230,12 +316,5 @@
       </method>
 
     </implementation>
-    <handlers>
-      <handler event="popuphiding">
-        <![CDATA[
-          this.closePicker();
-        ]]>
-      </handler>
-    </handlers>
   </binding>
 </bindings>
diff --git a/toolkit/content/widgets/spinner.js b/toolkit/content/widgets/spinner.js
index 059e151fc0..6ef929f8ad 100644
--- a/toolkit/content/widgets/spinner.js
+++ b/toolkit/content/widgets/spinner.js
@@ -299,11 +299,11 @@ function Spinner(props, context) {
             // An "active" class is needed to simulate :active pseudo-class
             // because element is not focused.
             event.target.classList.add("active");
-            this._smoothScrollToIndex(index + 1);
+            this._smoothScrollToIndex(index - 1);
           }
           if (event.target == down) {
             event.target.classList.add("active");
-            this._smoothScrollToIndex(index - 1);
+            this._smoothScrollToIndex(index + 1);
           }
           if (event.target.parentNode == spinner) {
             // Listen to dragging events
diff --git a/toolkit/locales/en-US/chrome/global/datetimebox.dtd b/toolkit/locales/en-US/chrome/global/datetimebox.dtd
new file mode 100644
index 0000000000..0deffa6b31
--- /dev/null
+++ b/toolkit/locales/en-US/chrome/global/datetimebox.dtd
@@ -0,0 +1,9 @@
+<!-- This Source Code Form is subject to the terms of the Mozilla Public
+   - License, v. 2.0. If a copy of the MPL was not distributed with this
+   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->
+
+<!-- Placeholders for input type=date -->
+
+<!ENTITY date.year.placeholder "yyyy">
+<!ENTITY date.month.placeholder "mm">
+<!ENTITY date.day.placeholder "dd">
diff --git a/toolkit/locales/jar.mn b/toolkit/locales/jar.mn
index e49e978f51..abc96086f5 100644
--- a/toolkit/locales/jar.mn
+++ b/toolkit/locales/jar.mn
@@ -39,6 +39,7 @@
   locale/@AB_CD@/global/customizeToolbar.dtd            (%chrome/global/customizeToolbar.dtd)
   locale/@AB_CD@/global/customizeToolbar.properties     (%chrome/global/customizeToolbar.properties)
 #endif
+  locale/@AB_CD@/global/datetimebox.dtd                 (%chrome/global/datetimebox.dtd)
   locale/@AB_CD@/global/datetimepicker.dtd              (%chrome/global/datetimepicker.dtd)
   locale/@AB_CD@/global/dateFormat.properties           (%chrome/global/dateFormat.properties)
   locale/@AB_CD@/global/dialogOverlay.dtd               (%chrome/global/dialogOverlay.dtd)
diff --git a/toolkit/modules/DateTimePickerHelper.jsm b/toolkit/modules/DateTimePickerHelper.jsm
index 769ae0094c..0ea96f226a 100644
--- a/toolkit/modules/DateTimePickerHelper.jsm
+++ b/toolkit/modules/DateTimePickerHelper.jsm
@@ -21,6 +21,7 @@ this.EXPORTED_SYMBOLS = [
 
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
 Cu.import("resource://gre/modules/Services.jsm");
+Cu.import("resource://gre/modules/Task.jsm");
 
 /*
  * DateTimePickerHelper receives message from content side (input box) and
@@ -66,6 +67,9 @@ this.DateTimePickerHelper = {
         break;
       }
       case "FormDateTime:UpdatePicker": {
+        if (!this.picker) {
+          return;
+        }
         this.picker.setPopupValue(aMessage.data);
         break;
       }
@@ -105,7 +109,7 @@ this.DateTimePickerHelper = {
   },
 
   // Get picker from browser and show it anchored to the input box.
-  showPicker: function(aBrowser, aData) {
+  showPicker: Task.async(function* (aBrowser, aData) {
     let rect = aData.rect;
     let dir = aData.dir;
     let type = aData.type;
@@ -135,13 +139,23 @@ this.DateTimePickerHelper = {
       debug("aBrowser.dateTimePicker not found, exiting now.");
       return;
     }
-    this.picker.loadPicker(type, detail);
+    // The datetimepopup binding is only attached when it is needed.
+    // Check if openPicker method is present to determine if binding has
+    // been attached. If not, attach the binding first before calling it.
+    if (!this.picker.openPicker) {
+      let bindingPromise = new Promise(resolve => {
+        this.picker.addEventListener("DateTimePickerBindingReady",
+                                     resolve, {once: true});
+      });
+      this.picker.setAttribute("active", true);
+      yield bindingPromise;
+    }
     // The arrow panel needs an anchor to work. The popupAnchor (this._anchor)
     // is a transparent div that the arrow can point to.
-    this.picker.openPopup(this._anchor, "after_start", 0, 0);
+    this.picker.openPicker(type, this._anchor, detail);
 
     this.addPickerListeners();
-  },
+  }),
 
   // Picker is closed, do some cleanup.
   close: function() {
diff --git a/toolkit/themes/shared/datetimeinputpickers.css b/toolkit/themes/shared/datetimeinputpickers.css
index 741f15281f..a0c046f6f1 100644
--- a/toolkit/themes/shared/datetimeinputpickers.css
+++ b/toolkit/themes/shared/datetimeinputpickers.css
@@ -12,7 +12,8 @@
   --colon-width: 2rem;
   --day-period-spacing-width: 1rem;
   --calendar-width: 23.1rem;
-  --date-picker-item-height: 2.4rem;
+  --date-picker-item-height: 2.5rem;
+  --date-picker-item-width: 3.3rem;
 
   --border: 0.1rem solid #D6D6D6;
   --border-radius: 0.3rem;
@@ -21,6 +22,8 @@
   --font-color: #191919;
   --fill-color: #EBEBEB;
 
+  --today-fill-color: rgb(212, 212, 212);
+
   --selected-font-color: #FFFFFF;
   --selected-fill-color: #0996F8;
 
@@ -29,10 +32,16 @@
   --button-font-color-active: #191919;
   --button-fill-color-active: #D4D4D4;
 
-  --weekday-font-color: #6C6C6C;
-  --weekday-outside-font-color: #6C6C6C;
-  --weekend-font-color: #DA4E44;
-  --weekend-outside-font-color: #FF988F;
+  --weekday-header-font-color: #6C6C6C;
+  --weekend-header-font-color: rgb(218, 78, 68);
+
+  --weekend-font-color: rgb(218, 78, 68);
+  --weekday-outside-font-color: rgb(153, 153, 153);
+  --weekend-outside-font-color: rgb(255, 152, 143);
+
+  --weekday-disabled-font-color: rgba(25, 25, 25, 0.2);
+  --weekend-disabled-font-color: rgba(218, 78, 68, 0.2);
+  --disabled-fill-color: rgba(235, 235, 235, 0.8);
 
   --disabled-opacity: 0.2;
 }
@@ -181,11 +190,11 @@ button.month-year.active::after {
 }
 
 .week-header > div {
-  color: var(--weekday-font-color);
+  color: var(--weekday-header-font-color);
 }
 
 .week-header > div.weekend {
-  color: var(--weekend-font-color);
+  color: var(--weekend-header-font-color);
 }
 
 .days-viewport {
@@ -206,24 +215,49 @@ button.month-year.active::after {
   align-items: center;
   display: flex;
   height: var(--date-picker-item-height);
-  margin: 0.05rem 0.15rem;
   position: relative;
   justify-content: center;
-  width: 3rem;
+  width: var(--date-picker-item-width);
 }
 
-.days-view > div.outside {
+.days-view > .outside {
   color: var(--weekday-outside-font-color);
 }
 
-.days-view > div.weekend {
+.days-view > .weekend {
   color: var(--weekend-font-color);
 }
 
-.days-view > div.weekend.outside {
+.days-view > .weekend.outside {
   color: var(--weekend-outside-font-color);
 }
 
+.days-view > .out-of-range {
+  color: var(--weekday-disabled-font-color);
+  background: var(--disabled-fill-color);
+}
+
+.days-view > .out-of-range.weekend {
+  color: var(--weekend-disabled-font-color);
+}
+
+.days-view > .today {
+  font-weight: bold;
+}
+
+.days-view > .out-of-range::before {
+  display: none;
+}
+
+.days-view > div:hover::before,
+.days-view > .select::before,
+.days-view > .today::before {
+  top: 5%;
+  bottom: 5%;
+  left: 5%;
+  right: 5%;
+}
+
 #time-picker,
 .month-year-view {
   display: flex;
@@ -283,22 +317,31 @@ button.month-year.active::after {
   scroll-snap-coordinate: 0 0;
 }
 
+.spinner-container > .spinner > div::before,
+.calendar-container .days-view > div::before {
+  position: absolute;
+  top: 5%;
+  bottom: 5%;
+  left: 5%;
+  right: 5%;
+  z-index: -10;
+  border-radius: var(--border-radius);
+}
+
 .spinner-container > .spinner > div:hover::before,
 .calendar-container .days-view > div:hover::before {
   background: var(--fill-color);
   border: var(--border);
-  border-radius: var(--border-radius);
   content: "";
-  position: absolute;
-  top: 0%;
-  bottom: 0%;
-  left: 0%;
-  right: 0%;
-  z-index: -10;
+}
+
+.calendar-container .days-view > div.today::before {
+  background: var(--today-fill-color);
+  content: "";
 }
 
 .spinner-container > .spinner:not(.scrolling) > div.selection,
-.calendar-container .days-view > div.selection {
+.calendar-container .days-view > div.selection:not(.out-of-range) {
   color: var(--selected-font-color);
 }
 
@@ -306,14 +349,7 @@ button.month-year.active::after {
 .calendar-container .days-view > div.selection::before {
   background: var(--selected-fill-color);
   border: none;
-  border-radius: var(--border-radius);
   content: "";
-  position: absolute;
-  top: 0%;
-  bottom: 0%;
-  left: 0%;
-  right: 0%;
-  z-index: -10;
 }
 
 .spinner-container > .spinner > div.disabled::before,