diff --git a/dom/bindings/parser/WebIDL.py b/dom/bindings/parser/WebIDL.py
index 08194a5aaf01..65f1afea713d 100644
--- a/dom/bindings/parser/WebIDL.py
+++ b/dom/bindings/parser/WebIDL.py
@@ -1084,18 +1084,11 @@ class IDLInterfaceOrNamespace(IDLInterfaceOrInterfaceMixinOrNamespace):
                     "Can't have both a constructor and [Global]",
                     [self.location, ctor.location])
 
-            assert(len(ctor._exposureGlobalNames) == 0 or
-                   ctor._exposureGlobalNames == self._exposureGlobalNames)
+            assert(ctor._exposureGlobalNames == self._exposureGlobalNames)
             ctor._exposureGlobalNames.update(self._exposureGlobalNames)
-            if ctor in self.members:
-                # constructor operation.
-                self.members.remove(ctor)
-            else:
-                # extended attribute.  This can only happen with
-                # [HTMLConstructor] and this is the only way we can get into this
-                # code with len(ctor._exposureGlobalNames) !=
-                # self._exposureGlobalNames.
-                ctor.finish(scope)
+            # Remove the constructor operation from our member list so
+            # it doesn't get in the way later.
+            self.members.remove(ctor)
 
         for ctor in self.namedConstructors:
             if self.globalNames:
@@ -1653,60 +1646,45 @@ class IDLInterface(IDLInterfaceOrNamespace):
                                       [attr.location])
 
                 self._noInterfaceObject = True
-            elif identifier == "NamedConstructor" or identifier == "HTMLConstructor":
-                if identifier == "NamedConstructor" and not attr.hasValue():
+            elif identifier == "NamedConstructor":
+                if not attr.hasValue():
                     raise WebIDLError("NamedConstructor must either take an identifier or take a named argument list",
                                       [attr.location])
 
-                if identifier == "HTMLConstructor":
-                    if not attr.noArguments():
-                        raise WebIDLError(str(identifier) + " must take no arguments",
-                                          [attr.location])
 
                 args = attr.args() if attr.hasArgs() else []
 
                 retType = IDLWrapperType(self.location, self)
 
-                if identifier == "HTMLConstructor":
-                    name = "constructor"
-                    allowForbidden = True
-                else:
-                    name = attr.value()
-                    allowForbidden = False
-
-                method = IDLConstructor(
-                    attr.location, args, name,
-                    htmlConstructor=(identifier == "HTMLConstructor"))
+                method = IDLConstructor(attr.location, args, attr.value())
                 method.reallyInit(self)
 
-                # Are always assumed to be able to throw (since there's no way to
-                # indicate otherwise).
+                # Named constructors are always assumed to be able to
+                # throw (since there's no way to indicate otherwise).
                 method.addExtendedAttributes(
                     [IDLExtendedAttribute(self.location, ("Throws",))])
 
-                if identifier == "HTMLConstructor":
-                    method.resolve(self)
-                else:
-                    # We need to detect conflicts for NamedConstructors across
-                    # interfaces. We first call resolve on the parentScope,
-                    # which will merge all NamedConstructors with the same
-                    # identifier accross interfaces as overloads.
-                    method.resolve(self.parentScope)
+                # We need to detect conflicts for NamedConstructors across
+                # interfaces. We first call resolve on the parentScope,
+                # which will merge all NamedConstructors with the same
+                # identifier accross interfaces as overloads.
+                method.resolve(self.parentScope)
 
-                    # Then we look up the identifier on the parentScope. If the
-                    # result is the same as the method we're adding then it
-                    # hasn't been added as an overload and it's the first time
-                    # we've encountered a NamedConstructor with that identifier.
-                    # If the result is not the same as the method we're adding
-                    # then it has been added as an overload and we need to check
-                    # whether the result is actually one of our existing
-                    # NamedConstructors.
-                    newMethod = self.parentScope.lookupIdentifier(method.identifier)
-                    if newMethod == method:
-                        self.namedConstructors.append(method)
-                    elif newMethod not in self.namedConstructors:
-                        raise WebIDLError("NamedConstructor conflicts with a NamedConstructor of a different interface",
-                                          [method.location, newMethod.location])
+                # Then we look up the identifier on the parentScope. If the
+                # result is the same as the method we're adding then it
+                # hasn't been added as an overload and it's the first time
+                # we've encountered a NamedConstructor with that identifier.
+                # If the result is not the same as the method we're adding
+                # then it has been added as an overload and we need to check
+                # whether the result is actually one of our existing
+                # NamedConstructors.
+                newMethod = self.parentScope.lookupIdentifier(method.identifier)
+                if newMethod == method:
+                    self.namedConstructors.append(method)
+                elif newMethod not in self.namedConstructors:
+                    raise WebIDLError("NamedConstructor conflicts with a "
+                                      "NamedConstructor of a different interface",
+                                      [method.location, newMethod.location])
             elif (identifier == "ExceptionClass"):
                 if not attr.noArguments():
                     raise WebIDLError("[ExceptionClass] must take no arguments",
@@ -4879,7 +4857,7 @@ class IDLMethod(IDLInterfaceMember, IDLScope):
                  static=False, getter=False, setter=False,
                  deleter=False, specialType=NamedOrIndexed.Neither,
                  legacycaller=False, stringifier=False,
-                 maplikeOrSetlikeOrIterable=None, htmlConstructor=False):
+                 maplikeOrSetlikeOrIterable=None):
         # REVIEW: specialType is NamedOrIndexed -- wow, this is messed up.
         IDLInterfaceMember.__init__(self, location, identifier,
                                     IDLInterfaceMember.Tags.Method)
@@ -4905,10 +4883,7 @@ class IDLMethod(IDLInterfaceMember, IDLScope):
         self._stringifier = stringifier
         assert maplikeOrSetlikeOrIterable is None or isinstance(maplikeOrSetlikeOrIterable, IDLMaplikeOrSetlikeOrIterableBase)
         self.maplikeOrSetlikeOrIterable = maplikeOrSetlikeOrIterable
-        assert isinstance(htmlConstructor, bool)
-        # The identifier of a HTMLConstructor must be 'constructor'.
-        assert not htmlConstructor or identifier.name == "constructor"
-        self._htmlConstructor = htmlConstructor
+        self._htmlConstructor = False
         self._specialType = specialType
         self._unforgeable = False
         self.dependsOn = "Everything"
@@ -5403,14 +5378,13 @@ class IDLMethod(IDLInterfaceMember, IDLScope):
 
 
 class IDLConstructor(IDLMethod):
-    def __init__(self, location, args, name, htmlConstructor=False):
+    def __init__(self, location, args, name):
         # We can't actually init our IDLMethod yet, because we do not know the
         # return type yet.  Just save the info we have for now and we will init
         # it later.
         self._initLocation = location
         self._initArgs = args
         self._initName = name
-        self._htmlConstructor = htmlConstructor
         self._inited = False
         self._initExtendedAttrs = []
 
@@ -5427,6 +5401,18 @@ class IDLConstructor(IDLMethod):
             identifier == "SecureContext" or
             identifier == "Throws"):
             IDLMethod.handleExtendedAttribute(self, attr)
+        elif identifier == "HTMLConstructor":
+            if not attr.noArguments():
+                raise WebIDLError("[HTMLConstructor] must take no arguments",
+                                  [attr.location])
+            # We shouldn't end up here for named constructors.
+            assert(self.identifier.name == "constructor")
+
+            if any(len(sig[1]) != 0 for sig in self.signatures()):
+                raise WebIDLError("[HTMLConstructor] must not be applied to a "
+                                  "constructor operation that has arguments.",
+                                  [attr.location])
+            self._htmlConstructor = True
         else:
             raise WebIDLError("Unknown extended attribute %s on method" % identifier,
                               [attr.location])
@@ -5437,7 +5423,7 @@ class IDLConstructor(IDLMethod):
         identifier = IDLUnresolvedIdentifier(location, name, allowForbidden=True)
         retType = IDLWrapperType(parentInterface.location, parentInterface)
         IDLMethod.__init__(self, location, identifier, retType, self._initArgs,
-                           static=True, htmlConstructor=self._htmlConstructor)
+                           static=True)
         self._inited = True;
         # Propagate through whatever extended attributes we already had
         self.addExtendedAttributes(self._initExtendedAttrs)
diff --git a/dom/bindings/parser/tests/test_constructor.py b/dom/bindings/parser/tests/test_constructor.py
index 20eb152cdabf..721f9c2089eb 100644
--- a/dom/bindings/parser/tests/test_constructor.py
+++ b/dom/bindings/parser/tests/test_constructor.py
@@ -105,8 +105,8 @@ def WebIDLTest(parser, harness):
 
     parser = parser.reset()
     parser.parse("""
-        [HTMLConstructor]
         interface TestHTMLConstructor {
+          [HTMLConstructor] constructor();
         };
     """)
     results = parser.finish()
@@ -138,8 +138,8 @@ def WebIDLTest(parser, harness):
     threw = False
     try:
         parser.parse("""
-            [HTMLConstructor(DOMString a)]
             interface TestHTMLConstructorWithArgs {
+              [HTMLConstructor] constructor(DOMString a);
             };
         """)
         results = parser.finish()
@@ -153,8 +153,8 @@ def WebIDLTest(parser, harness):
     threw = False
     try:
         parser.parse("""
-            [HTMLConstructor]
             callback interface TestHTMLConstructorOnCallbackInterface {
+              [HTMLConstructor] constructor();
             };
         """)
         results = parser.finish()
@@ -168,9 +168,9 @@ def WebIDLTest(parser, harness):
     threw = False
     try:
         parser.parse("""
-            [HTMLConstructor]
             interface TestHTMLConstructorAndConstructor {
               constructor();
+              [HTMLConstructor] constructor();
             };
         """)
         results = parser.finish()
@@ -183,10 +183,10 @@ def WebIDLTest(parser, harness):
     threw = False
     try:
         parser.parse("""
-            [HTMLConstructor]
             interface TestHTMLConstructorAndConstructor {
               [Throws]
               constructor();
+              [HTMLConstructor] constructor();
             };
         """)
         results = parser.finish()
@@ -200,9 +200,9 @@ def WebIDLTest(parser, harness):
     threw = False
     try:
         parser.parse("""
-            [HTMLConstructor]
             interface TestHTMLConstructorAndConstructor {
               constructor(DOMString a);
+              [HTMLConstructor] constructor();
             };
         """)
         results = parser.finish()
@@ -216,10 +216,10 @@ def WebIDLTest(parser, harness):
     threw = False
     try:
         parser.parse("""
-            [HTMLConstructor]
             interface TestHTMLConstructorAndConstructor {
               [Throws]
               constructor(DOMString a);
+              [HTMLConstructor] constructor();
             };
         """)
         results = parser.finish()
@@ -235,10 +235,10 @@ def WebIDLTest(parser, harness):
     threw = False
     try:
         parser.parse("""
-            [HTMLConstructor]
             interface TestHTMLConstructorAndConstructor {
               [ChromeOnly]
               constructor();
+              [HTMLConstructor] constructor();
             };
         """)
         results = parser.finish()
@@ -252,10 +252,10 @@ def WebIDLTest(parser, harness):
     threw = False
     try:
         parser.parse("""
-            [HTMLConstructor]
             interface TestHTMLConstructorAndConstructor {
               [Throws, ChromeOnly]
               constructor();
+              [HTMLConstructor] constructor();
             };
         """)
         results = parser.finish()
@@ -270,10 +270,10 @@ def WebIDLTest(parser, harness):
     threw = False
     try:
         parser.parse("""
-            [HTMLConstructor]
             interface TestHTMLConstructorAndConstructor {
               [ChromeOnly]
               constructor(DOMString a);
+              [HTMLConstructor] constructor();
             };
         """)
         results = parser.finish()
@@ -288,10 +288,10 @@ def WebIDLTest(parser, harness):
     threw = False
     try:
         parser.parse("""
-            [HTMLConstructor]
             interface TestHTMLConstructorAndConstructor {
               [Throws, ChromeOnly]
               constructor(DOMString a);
+              [HTMLConstructor] constructor();
             };
         """)
         results = parser.finish()
diff --git a/dom/bindings/parser/tests/test_constructor_global.py b/dom/bindings/parser/tests/test_constructor_global.py
index 31c5d95317f5..b7eabb1e35b6 100644
--- a/dom/bindings/parser/tests/test_constructor_global.py
+++ b/dom/bindings/parser/tests/test_constructor_global.py
@@ -50,23 +50,9 @@ def WebIDLTest(parser, harness):
     threw = False
     try:
         parser.parse("""
-            [Global, HTMLConstructor, Exposed=TestHTMLConstructorGlobal]
-            interface TestHTMLConstructorGlobal {
-            };
-        """)
-
-        results = parser.finish()
-    except:
-        threw = True
-
-    harness.ok(threw, "Should have thrown.")
-
-    parser = parser.reset()
-    threw = False
-    try:
-        parser.parse("""
-            [HTMLConstructor, Global, Exposed=TestHTMLConstructorGlobal]
+            [Global, Exposed=TestHTMLConstructorGlobal]
             interface TestHTMLConstructorGlobal {
+              [HTMLConstructor] constructor();
             };
         """)
 
diff --git a/dom/bindings/parser/tests/test_constructor_no_interface_object.py b/dom/bindings/parser/tests/test_constructor_no_interface_object.py
index d41750949117..24cc36066cd6 100644
--- a/dom/bindings/parser/tests/test_constructor_no_interface_object.py
+++ b/dom/bindings/parser/tests/test_constructor_no_interface_object.py
@@ -28,24 +28,9 @@ def WebIDLTest(parser, harness):
     threw = False
     try:
         parser.parse("""
-            [NoInterfaceObject, HTMLConstructor]
-            interface TestHTMLConstructorNoInterfaceObject {
-            };
-        """)
-
-        results = parser.finish()
-    except:
-        threw = True
-
-    harness.ok(threw, "Should have thrown.")
-
-    parser = parser.reset()
-
-    threw = False
-    try:
-        parser.parse("""
-            [HTMLConstructor, NoInterfaceObject]
+            [NoInterfaceObject]
             interface TestHTMLConstructorNoInterfaceObject {
+              [HTMLConstructor] constructor();
             };
         """)
 
diff --git a/dom/bindings/test/TestCodeGen.webidl b/dom/bindings/test/TestCodeGen.webidl
index 3c23083ddcf1..b83818b6e4e7 100644
--- a/dom/bindings/test/TestCodeGen.webidl
+++ b/dom/bindings/test/TestCodeGen.webidl
@@ -1327,9 +1327,9 @@ interface TestWorkerExposedInterface {
   [NeedsSubjectPrincipal=NonSystem] attribute boolean needsNonSystemSubjectPrincipalAttr;
 };
 
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface TestHTMLConstructorInterface {
+  [HTMLConstructor] constructor();
 };
 
 [Exposed=Window]
diff --git a/dom/chrome-webidl/XULFrameElement.webidl b/dom/chrome-webidl/XULFrameElement.webidl
index d56fca32b5cd..84db8cadfb68 100644
--- a/dom/chrome-webidl/XULFrameElement.webidl
+++ b/dom/chrome-webidl/XULFrameElement.webidl
@@ -6,10 +6,12 @@
 interface nsIDocShell;
 interface nsIWebNavigation;
 
-[HTMLConstructor, Func="IsChromeOrXBL",
+[Func="IsChromeOrXBL",
  Exposed=Window]
 interface XULFrameElement : XULElement
 {
+  [HTMLConstructor] constructor();
+
   readonly attribute nsIDocShell? docShell;
   readonly attribute nsIWebNavigation? webNavigation;
 
diff --git a/dom/chrome-webidl/XULMenuElement.webidl b/dom/chrome-webidl/XULMenuElement.webidl
index b07f696ab5e2..7aa6e067c67e 100644
--- a/dom/chrome-webidl/XULMenuElement.webidl
+++ b/dom/chrome-webidl/XULMenuElement.webidl
@@ -5,9 +5,10 @@
  * You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
-[HTMLConstructor, Func="IsChromeOrXBL",
+[Func="IsChromeOrXBL",
  Exposed=Window]
 interface XULMenuElement : XULElement {
+  [HTMLConstructor] constructor();
 
   attribute Element? activeChild;
 
diff --git a/dom/chrome-webidl/XULTextElement.webidl b/dom/chrome-webidl/XULTextElement.webidl
index 13f4140d33a3..c54f54e9a2f7 100644
--- a/dom/chrome-webidl/XULTextElement.webidl
+++ b/dom/chrome-webidl/XULTextElement.webidl
@@ -5,9 +5,11 @@
  * You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
-[HTMLConstructor, Func="IsChromeOrXBL",
+[Func="IsChromeOrXBL",
  Exposed=Window]
 interface XULTextElement : XULElement {
+  [HTMLConstructor] constructor();
+
   attribute boolean disabled;
   attribute DOMString value;
   attribute DOMString accessKey;
diff --git a/dom/chrome-webidl/XULTreeElement.webidl b/dom/chrome-webidl/XULTreeElement.webidl
index d7c0646c7798..8f09de4f1d20 100644
--- a/dom/chrome-webidl/XULTreeElement.webidl
+++ b/dom/chrome-webidl/XULTreeElement.webidl
@@ -13,10 +13,12 @@ dictionary TreeCellInfo {
     DOMString childElt = "";
 };
 
-[HTMLConstructor, Func="IsChromeOrXBL",
+[Func="IsChromeOrXBL",
  Exposed=Window]
 interface XULTreeElement : XULElement
 {
+  [HTMLConstructor] constructor();
+
   /**
    * Obtain the columns.
    */
diff --git a/dom/webidl/HTMLAnchorElement.webidl b/dom/webidl/HTMLAnchorElement.webidl
index 623ebaee4cb4..3ca7455f4ce3 100644
--- a/dom/webidl/HTMLAnchorElement.webidl
+++ b/dom/webidl/HTMLAnchorElement.webidl
@@ -12,9 +12,10 @@
  */
 
 // http://www.whatwg.org/specs/web-apps/current-work/#the-a-element
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLAnchorElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
            [CEReactions, SetterThrows]
            attribute DOMString target;
            [CEReactions, SetterThrows]
diff --git a/dom/webidl/HTMLAreaElement.webidl b/dom/webidl/HTMLAreaElement.webidl
index e4c01a23983b..7bef4a316c3d 100644
--- a/dom/webidl/HTMLAreaElement.webidl
+++ b/dom/webidl/HTMLAreaElement.webidl
@@ -13,9 +13,10 @@
  */
 
 // http://www.whatwg.org/specs/web-apps/current-work/#the-area-element
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLAreaElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
            [CEReactions, SetterThrows]
            attribute DOMString alt;
            [CEReactions, SetterThrows]
diff --git a/dom/webidl/HTMLAudioElement.webidl b/dom/webidl/HTMLAudioElement.webidl
index 7172cb471863..54142f317ca7 100644
--- a/dom/webidl/HTMLAudioElement.webidl
+++ b/dom/webidl/HTMLAudioElement.webidl
@@ -11,7 +11,9 @@
  * and create derivative works of this document.
  */
 
-[HTMLConstructor, NamedConstructor=Audio(optional DOMString src),
+[NamedConstructor=Audio(optional DOMString src),
  Exposed=Window]
-interface HTMLAudioElement : HTMLMediaElement {};
+interface HTMLAudioElement : HTMLMediaElement {
+  [HTMLConstructor] constructor();
+};
 
diff --git a/dom/webidl/HTMLBRElement.webidl b/dom/webidl/HTMLBRElement.webidl
index e73145d02dca..9762fda0195e 100644
--- a/dom/webidl/HTMLBRElement.webidl
+++ b/dom/webidl/HTMLBRElement.webidl
@@ -13,9 +13,10 @@
  */
 
 // http://www.whatwg.org/specs/web-apps/current-work/#the-br-element
-[HTMLConstructor,
- Exposed=Window]
-interface HTMLBRElement : HTMLElement {};
+[Exposed=Window]
+interface HTMLBRElement : HTMLElement {
+  [HTMLConstructor] constructor();
+};
 
 // http://www.whatwg.org/specs/web-apps/current-work/#other-elements,-attributes-and-apis
 partial interface HTMLBRElement {
diff --git a/dom/webidl/HTMLBaseElement.webidl b/dom/webidl/HTMLBaseElement.webidl
index af0b76e6fc7b..17b67bad3834 100644
--- a/dom/webidl/HTMLBaseElement.webidl
+++ b/dom/webidl/HTMLBaseElement.webidl
@@ -12,9 +12,10 @@
  */
 
 // http://www.whatwg.org/specs/web-apps/current-work/#the-base-element
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLBaseElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
            [CEReactions, SetterThrows, Pure]
            attribute DOMString href;
            [CEReactions, SetterThrows, Pure]
diff --git a/dom/webidl/HTMLBodyElement.webidl b/dom/webidl/HTMLBodyElement.webidl
index 6cec91919242..1038adb45f44 100644
--- a/dom/webidl/HTMLBodyElement.webidl
+++ b/dom/webidl/HTMLBodyElement.webidl
@@ -11,9 +11,10 @@
  * and create derivative works of this document.
  */
 
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLBodyElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
 };
 
 partial interface HTMLBodyElement {
diff --git a/dom/webidl/HTMLButtonElement.webidl b/dom/webidl/HTMLButtonElement.webidl
index 5ec108851987..b76d8cc73fb5 100644
--- a/dom/webidl/HTMLButtonElement.webidl
+++ b/dom/webidl/HTMLButtonElement.webidl
@@ -11,9 +11,10 @@
  */
 
 // http://www.whatwg.org/specs/web-apps/current-work/#the-button-element
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLButtonElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
   [CEReactions, SetterThrows, Pure]
            attribute boolean autofocus;
   [CEReactions, SetterThrows, Pure]
diff --git a/dom/webidl/HTMLCanvasElement.webidl b/dom/webidl/HTMLCanvasElement.webidl
index 959f62477f9e..1ecd479afcdf 100644
--- a/dom/webidl/HTMLCanvasElement.webidl
+++ b/dom/webidl/HTMLCanvasElement.webidl
@@ -13,9 +13,10 @@
 interface nsISupports;
 interface Variant;
 
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLCanvasElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
   [CEReactions, Pure, SetterThrows]
            attribute unsigned long width;
   [CEReactions, Pure, SetterThrows]
diff --git a/dom/webidl/HTMLDListElement.webidl b/dom/webidl/HTMLDListElement.webidl
index c72dd0bb9d6c..00afe405b62d 100644
--- a/dom/webidl/HTMLDListElement.webidl
+++ b/dom/webidl/HTMLDListElement.webidl
@@ -13,9 +13,10 @@
  */
 
 // http://www.whatwg.org/specs/web-apps/current-work/#the-dl-element
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLDListElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
 };
 
 // http://www.whatwg.org/specs/web-apps/current-work/#other-elements,-attributes-and-apis
diff --git a/dom/webidl/HTMLDataElement.webidl b/dom/webidl/HTMLDataElement.webidl
index aef7a2d8a649..1a04747e752f 100644
--- a/dom/webidl/HTMLDataElement.webidl
+++ b/dom/webidl/HTMLDataElement.webidl
@@ -7,9 +7,10 @@
  * http://www.whatwg.org/specs/web-apps/current-work/multipage/text-level-semantics.html#the-data-element
  */
 
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLDataElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
            [CEReactions, SetterThrows]
            attribute DOMString value;
 };
diff --git a/dom/webidl/HTMLDataListElement.webidl b/dom/webidl/HTMLDataListElement.webidl
index 88b2a0ebbe26..23c462a3b79c 100644
--- a/dom/webidl/HTMLDataListElement.webidl
+++ b/dom/webidl/HTMLDataListElement.webidl
@@ -11,8 +11,9 @@
  * and create derivative works of this document.
  */
 
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLDataListElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
   readonly attribute HTMLCollection options;
 };
diff --git a/dom/webidl/HTMLDetailsElement.webidl b/dom/webidl/HTMLDetailsElement.webidl
index 69eda0c080c6..7f293f8ed829 100644
--- a/dom/webidl/HTMLDetailsElement.webidl
+++ b/dom/webidl/HTMLDetailsElement.webidl
@@ -11,9 +11,10 @@
  * and create derivative works of this document.
  */
 
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLDetailsElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
   [CEReactions, SetterThrows]
   attribute boolean open;
 };
diff --git a/dom/webidl/HTMLDialogElement.webidl b/dom/webidl/HTMLDialogElement.webidl
index c220e26a3270..38b035f24773 100644
--- a/dom/webidl/HTMLDialogElement.webidl
+++ b/dom/webidl/HTMLDialogElement.webidl
@@ -11,9 +11,11 @@
  * and create derivative works of this document.
  */
 
-[Pref="dom.dialog_element.enabled", HTMLConstructor,
+[Pref="dom.dialog_element.enabled",
  Exposed=Window]
 interface HTMLDialogElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
   [CEReactions, SetterThrows]
   attribute boolean open;
   attribute DOMString returnValue;
diff --git a/dom/webidl/HTMLDirectoryElement.webidl b/dom/webidl/HTMLDirectoryElement.webidl
index 073af9a297be..69624d541e92 100644
--- a/dom/webidl/HTMLDirectoryElement.webidl
+++ b/dom/webidl/HTMLDirectoryElement.webidl
@@ -12,9 +12,10 @@
  */
 
 // http://www.whatwg.org/specs/web-apps/current-work/#other-elements,-attributes-and-apis
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLDirectoryElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
            [CEReactions, SetterThrows, Pure]
            attribute boolean compact;
 };
diff --git a/dom/webidl/HTMLDivElement.webidl b/dom/webidl/HTMLDivElement.webidl
index 2249df124024..c61b82df972c 100644
--- a/dom/webidl/HTMLDivElement.webidl
+++ b/dom/webidl/HTMLDivElement.webidl
@@ -11,9 +11,10 @@
  * and create derivative works of this document.
  */
 
-[HTMLConstructor,
- Exposed=Window]
-interface HTMLDivElement : HTMLElement {};
+[Exposed=Window]
+interface HTMLDivElement : HTMLElement {
+  [HTMLConstructor] constructor();
+};
 
 partial interface HTMLDivElement {
   [CEReactions, SetterThrows]
diff --git a/dom/webidl/HTMLElement.webidl b/dom/webidl/HTMLElement.webidl
index d5e648a7cae5..081f37c7e07e 100644
--- a/dom/webidl/HTMLElement.webidl
+++ b/dom/webidl/HTMLElement.webidl
@@ -12,9 +12,10 @@
  * and create derivative works of this document.
  */
 
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLElement : Element {
+  [HTMLConstructor] constructor();
+
   // metadata attributes
   [CEReactions]
            attribute DOMString title;
diff --git a/dom/webidl/HTMLEmbedElement.webidl b/dom/webidl/HTMLEmbedElement.webidl
index 95658bf07805..01ebced01551 100644
--- a/dom/webidl/HTMLEmbedElement.webidl
+++ b/dom/webidl/HTMLEmbedElement.webidl
@@ -13,9 +13,11 @@
  */
 
 // http://www.whatwg.org/specs/web-apps/current-work/#the-embed-element
-[HTMLConstructor, NeedResolve,
+[NeedResolve,
  Exposed=Window]
 interface HTMLEmbedElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
   [CEReactions, Pure, SetterThrows]
            attribute DOMString src;
   [CEReactions, Pure, SetterThrows]
diff --git a/dom/webidl/HTMLFieldSetElement.webidl b/dom/webidl/HTMLFieldSetElement.webidl
index 36f99db80851..cc53202b8051 100644
--- a/dom/webidl/HTMLFieldSetElement.webidl
+++ b/dom/webidl/HTMLFieldSetElement.webidl
@@ -11,9 +11,10 @@
  * and create derivative works of this document.
  */
 
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLFieldSetElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
   [CEReactions, SetterThrows]
            attribute boolean disabled;
   readonly attribute HTMLFormElement? form;
diff --git a/dom/webidl/HTMLFontElement.webidl b/dom/webidl/HTMLFontElement.webidl
index b16941a0aa9d..f400b5d11f5f 100644
--- a/dom/webidl/HTMLFontElement.webidl
+++ b/dom/webidl/HTMLFontElement.webidl
@@ -11,9 +11,10 @@
  * and create derivative works of this document.
  */
 
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLFontElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
   [CEReactions, SetterThrows] attribute [TreatNullAs=EmptyString] DOMString color;
   [CEReactions, SetterThrows]                          attribute DOMString face;
   [CEReactions, SetterThrows]                          attribute DOMString size;
diff --git a/dom/webidl/HTMLFormElement.webidl b/dom/webidl/HTMLFormElement.webidl
index 24b3cf6bfd37..6da88e2f39dd 100644
--- a/dom/webidl/HTMLFormElement.webidl
+++ b/dom/webidl/HTMLFormElement.webidl
@@ -11,9 +11,11 @@
  * and create derivative works of this document.
  */
 
-[OverrideBuiltins, LegacyUnenumerableNamedProperties, HTMLConstructor,
+[OverrideBuiltins, LegacyUnenumerableNamedProperties,
  Exposed=Window]
 interface HTMLFormElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
            [CEReactions, Pure, SetterThrows]
            attribute DOMString acceptCharset;
            [CEReactions, Pure, SetterThrows]
diff --git a/dom/webidl/HTMLFrameElement.webidl b/dom/webidl/HTMLFrameElement.webidl
index 654662d9025c..2409298f411e 100644
--- a/dom/webidl/HTMLFrameElement.webidl
+++ b/dom/webidl/HTMLFrameElement.webidl
@@ -11,9 +11,10 @@
  */
 
 // http://www.whatwg.org/specs/web-apps/current-work/#htmlframeelement
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLFrameElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
            [CEReactions, SetterThrows]
            attribute DOMString name;
            [CEReactions, SetterThrows]
diff --git a/dom/webidl/HTMLFrameSetElement.webidl b/dom/webidl/HTMLFrameSetElement.webidl
index e603bc4ae029..49e6c549563e 100644
--- a/dom/webidl/HTMLFrameSetElement.webidl
+++ b/dom/webidl/HTMLFrameSetElement.webidl
@@ -11,9 +11,10 @@
  * and create derivative works of this document.
  */
 
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLFrameSetElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
   [CEReactions, SetterThrows]
   attribute DOMString cols;
   [CEReactions, SetterThrows]
diff --git a/dom/webidl/HTMLHRElement.webidl b/dom/webidl/HTMLHRElement.webidl
index 378affb3bd48..b73c2589dbeb 100644
--- a/dom/webidl/HTMLHRElement.webidl
+++ b/dom/webidl/HTMLHRElement.webidl
@@ -12,9 +12,10 @@
  */
 
 // http://www.whatwg.org/specs/web-apps/current-work/#the-hr-element
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLHRElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
 };
 
 // http://www.whatwg.org/specs/web-apps/current-work/#other-elements,-attributes-and-apis
diff --git a/dom/webidl/HTMLHeadElement.webidl b/dom/webidl/HTMLHeadElement.webidl
index d5273d5045e8..0524a6d8f131 100644
--- a/dom/webidl/HTMLHeadElement.webidl
+++ b/dom/webidl/HTMLHeadElement.webidl
@@ -12,7 +12,8 @@
  */
 
 // http://www.whatwg.org/specs/web-apps/current-work/#the-head-element
-[HTMLConstructor,
- Exposed=Window]
-interface HTMLHeadElement : HTMLElement {};
+[Exposed=Window]
+interface HTMLHeadElement : HTMLElement {
+  [HTMLConstructor] constructor();
+};
 
diff --git a/dom/webidl/HTMLHeadingElement.webidl b/dom/webidl/HTMLHeadingElement.webidl
index d298c8a87e3f..0092388e96ea 100644
--- a/dom/webidl/HTMLHeadingElement.webidl
+++ b/dom/webidl/HTMLHeadingElement.webidl
@@ -12,9 +12,10 @@
  */
 
 // http://www.whatwg.org/specs/web-apps/current-work/#the-h1,-h2,-h3,-h4,-h5,-and-h6-elements
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLHeadingElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
 };
 
 // http://www.whatwg.org/specs/web-apps/current-work/#other-elements,-attributes-and-apis
diff --git a/dom/webidl/HTMLHtmlElement.webidl b/dom/webidl/HTMLHtmlElement.webidl
index 30efaec5015b..38f1b3bc53e4 100644
--- a/dom/webidl/HTMLHtmlElement.webidl
+++ b/dom/webidl/HTMLHtmlElement.webidl
@@ -13,9 +13,10 @@
  */
 
 // http://www.whatwg.org/specs/web-apps/current-work/#the-html-element
-[HTMLConstructor,
- Exposed=Window]
-interface HTMLHtmlElement : HTMLElement {};
+[Exposed=Window]
+interface HTMLHtmlElement : HTMLElement {
+  [HTMLConstructor] constructor();
+};
 
 // http://www.whatwg.org/specs/web-apps/current-work/#other-elements,-attributes-and-apis
 partial interface HTMLHtmlElement {
diff --git a/dom/webidl/HTMLIFrameElement.webidl b/dom/webidl/HTMLIFrameElement.webidl
index 60f5ddd28c92..fc786738e478 100644
--- a/dom/webidl/HTMLIFrameElement.webidl
+++ b/dom/webidl/HTMLIFrameElement.webidl
@@ -13,9 +13,10 @@
  * and create derivative works of this document.
  */
 
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLIFrameElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
   [CEReactions, SetterNeedsSubjectPrincipal=NonSystem, SetterThrows, Pure]
            attribute DOMString src;
   [CEReactions, SetterThrows, Pure]
diff --git a/dom/webidl/HTMLImageElement.webidl b/dom/webidl/HTMLImageElement.webidl
index 0fb2d1ca3bd4..9e3daa7f7563 100644
--- a/dom/webidl/HTMLImageElement.webidl
+++ b/dom/webidl/HTMLImageElement.webidl
@@ -16,10 +16,11 @@ interface imgIRequest;
 interface URI;
 interface nsIStreamListener;
 
-[HTMLConstructor,
- NamedConstructor=Image(optional unsigned long width, optional unsigned long height),
+[NamedConstructor=Image(optional unsigned long width, optional unsigned long height),
  Exposed=Window]
 interface HTMLImageElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
            [CEReactions, SetterThrows]
            attribute DOMString alt;
            [CEReactions, SetterNeedsSubjectPrincipal=NonSystem, SetterThrows]
diff --git a/dom/webidl/HTMLInputElement.webidl b/dom/webidl/HTMLInputElement.webidl
index bb708365a741..bd9c1eb2b33f 100644
--- a/dom/webidl/HTMLInputElement.webidl
+++ b/dom/webidl/HTMLInputElement.webidl
@@ -22,9 +22,10 @@ enum SelectionMode {
 
 interface XULControllers;
 
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLInputElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
   [CEReactions, Pure, SetterThrows]
            attribute DOMString accept;
   [CEReactions, Pure, SetterThrows]
diff --git a/dom/webidl/HTMLLIElement.webidl b/dom/webidl/HTMLLIElement.webidl
index 359b051675e7..f6a667102f9e 100644
--- a/dom/webidl/HTMLLIElement.webidl
+++ b/dom/webidl/HTMLLIElement.webidl
@@ -13,9 +13,10 @@
  */
 
 // http://www.whatwg.org/specs/web-apps/current-work/#the-li-element
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLLIElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
            [CEReactions, SetterThrows, Pure]
            attribute long value;
 };
diff --git a/dom/webidl/HTMLLabelElement.webidl b/dom/webidl/HTMLLabelElement.webidl
index 73cf4fe780ff..6f78a19339da 100644
--- a/dom/webidl/HTMLLabelElement.webidl
+++ b/dom/webidl/HTMLLabelElement.webidl
@@ -11,9 +11,10 @@
  * and create derivative works of this document.
  */
 
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLLabelElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
   readonly attribute HTMLFormElement? form;
   [CEReactions]
            attribute DOMString htmlFor;
diff --git a/dom/webidl/HTMLLegendElement.webidl b/dom/webidl/HTMLLegendElement.webidl
index 2e0cf4e3403b..075af8b1a9c0 100644
--- a/dom/webidl/HTMLLegendElement.webidl
+++ b/dom/webidl/HTMLLegendElement.webidl
@@ -13,9 +13,10 @@
  */
 
 // http://www.whatwg.org/specs/web-apps/current-work/#the-legend-element
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLLegendElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
   readonly attribute HTMLFormElement? form;
 };
 
diff --git a/dom/webidl/HTMLLinkElement.webidl b/dom/webidl/HTMLLinkElement.webidl
index 98658e1e9dc9..dbde671bc7dc 100644
--- a/dom/webidl/HTMLLinkElement.webidl
+++ b/dom/webidl/HTMLLinkElement.webidl
@@ -12,9 +12,10 @@
  */
 
 // http://www.whatwg.org/specs/web-apps/current-work/#the-link-element
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLLinkElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
   [CEReactions, SetterThrows, Pure]
            attribute boolean disabled;
   [CEReactions, SetterNeedsSubjectPrincipal=NonSystem, SetterThrows, Pure]
diff --git a/dom/webidl/HTMLMapElement.webidl b/dom/webidl/HTMLMapElement.webidl
index 1e241a15b496..038fd108e16d 100644
--- a/dom/webidl/HTMLMapElement.webidl
+++ b/dom/webidl/HTMLMapElement.webidl
@@ -11,9 +11,10 @@
  */
 
 // http://www.whatwg.org/specs/web-apps/current-work/#the-map-element
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLMapElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
   [CEReactions, SetterThrows, Pure]
            attribute DOMString name;
   [Constant]
diff --git a/dom/webidl/HTMLMarqueeElement.webidl b/dom/webidl/HTMLMarqueeElement.webidl
index d8b3236c721b..a755dc6c48e4 100644
--- a/dom/webidl/HTMLMarqueeElement.webidl
+++ b/dom/webidl/HTMLMarqueeElement.webidl
@@ -12,9 +12,10 @@
 
 // https://html.spec.whatwg.org/multipage/obsolete.html#the-marquee-element
 
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLMarqueeElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
   [CEReactions, SetterThrows] attribute DOMString behavior;
   [CEReactions, SetterThrows] attribute DOMString bgColor;
   [CEReactions, SetterThrows] attribute DOMString direction;
diff --git a/dom/webidl/HTMLMenuElement.webidl b/dom/webidl/HTMLMenuElement.webidl
index 6262ce7e7a29..c2c027fd3992 100644
--- a/dom/webidl/HTMLMenuElement.webidl
+++ b/dom/webidl/HTMLMenuElement.webidl
@@ -15,9 +15,10 @@
 interface MenuBuilder;
 
 // http://www.whatwg.org/specs/web-apps/current-work/#the-menu-element
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLMenuElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
            [CEReactions, SetterThrows]
            attribute DOMString type;
            [CEReactions, SetterThrows]
diff --git a/dom/webidl/HTMLMenuItemElement.webidl b/dom/webidl/HTMLMenuItemElement.webidl
index fd3f4842c72d..ccaae36e13f7 100644
--- a/dom/webidl/HTMLMenuItemElement.webidl
+++ b/dom/webidl/HTMLMenuItemElement.webidl
@@ -12,9 +12,10 @@
  */
 
 // http://www.whatwg.org/specs/web-apps/current-work/#the-menuitem-element
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLMenuItemElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
            [CEReactions, SetterThrows]
            attribute DOMString type;
            [CEReactions, SetterThrows]
diff --git a/dom/webidl/HTMLMetaElement.webidl b/dom/webidl/HTMLMetaElement.webidl
index ebb0c3fec321..148203f5d8eb 100644
--- a/dom/webidl/HTMLMetaElement.webidl
+++ b/dom/webidl/HTMLMetaElement.webidl
@@ -12,9 +12,10 @@
  */
 
 // http://www.whatwg.org/specs/web-apps/current-work/#the-meta-element
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLMetaElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
   [CEReactions, SetterThrows, Pure]
            attribute DOMString name;
   [CEReactions, SetterThrows, Pure]
diff --git a/dom/webidl/HTMLMeterElement.webidl b/dom/webidl/HTMLMeterElement.webidl
index cd2aacbe1bec..36a6a1d8f579 100644
--- a/dom/webidl/HTMLMeterElement.webidl
+++ b/dom/webidl/HTMLMeterElement.webidl
@@ -12,9 +12,10 @@
  */
 
 // http://www.whatwg.org/specs/web-apps/current-work/#the-meter-element
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLMeterElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
            [CEReactions, SetterThrows]
            attribute double value;
            [CEReactions, SetterThrows]
diff --git a/dom/webidl/HTMLModElement.webidl b/dom/webidl/HTMLModElement.webidl
index f89a5bcac8a7..afc040123bc7 100644
--- a/dom/webidl/HTMLModElement.webidl
+++ b/dom/webidl/HTMLModElement.webidl
@@ -11,9 +11,10 @@
  */
 
 // http://www.whatwg.org/specs/web-apps/current-work/#attributes-common-to-ins-and-del-elements
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLModElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
   [CEReactions, SetterThrows, Pure]
            attribute DOMString cite;
   [CEReactions, SetterThrows, Pure]
diff --git a/dom/webidl/HTMLOListElement.webidl b/dom/webidl/HTMLOListElement.webidl
index 8e3041067db6..269c4bfd1e17 100644
--- a/dom/webidl/HTMLOListElement.webidl
+++ b/dom/webidl/HTMLOListElement.webidl
@@ -13,9 +13,10 @@
  */
 
 // http://www.whatwg.org/specs/web-apps/current-work/#the-ol-element
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLOListElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
            [CEReactions, SetterThrows]
            attribute boolean reversed;
            [CEReactions, SetterThrows]
diff --git a/dom/webidl/HTMLObjectElement.webidl b/dom/webidl/HTMLObjectElement.webidl
index 5589a8589c60..53f0cc622161 100644
--- a/dom/webidl/HTMLObjectElement.webidl
+++ b/dom/webidl/HTMLObjectElement.webidl
@@ -13,9 +13,11 @@
  */
 
 // http://www.whatwg.org/specs/web-apps/current-work/#the-object-element
-[HTMLConstructor, NeedResolve,
+[NeedResolve,
  Exposed=Window]
 interface HTMLObjectElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
   [CEReactions, Pure, SetterThrows]
            attribute DOMString data;
   [CEReactions, Pure, SetterThrows]
diff --git a/dom/webidl/HTMLOptGroupElement.webidl b/dom/webidl/HTMLOptGroupElement.webidl
index b674b1af0472..926c59a31d98 100644
--- a/dom/webidl/HTMLOptGroupElement.webidl
+++ b/dom/webidl/HTMLOptGroupElement.webidl
@@ -11,9 +11,10 @@
  * and create derivative works of this document.
  */
 
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLOptGroupElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
            [CEReactions, SetterThrows]
            attribute boolean disabled;
            [CEReactions, SetterThrows]
diff --git a/dom/webidl/HTMLOptionElement.webidl b/dom/webidl/HTMLOptionElement.webidl
index d952ba0e0697..9b04a517eefe 100644
--- a/dom/webidl/HTMLOptionElement.webidl
+++ b/dom/webidl/HTMLOptionElement.webidl
@@ -11,9 +11,11 @@
  * and create derivative works of this document.
  */
 
-[HTMLConstructor, NamedConstructor=Option(optional DOMString text = "", optional DOMString value, optional boolean defaultSelected = false, optional boolean selected = false),
+[NamedConstructor=Option(optional DOMString text = "", optional DOMString value, optional boolean defaultSelected = false, optional boolean selected = false),
  Exposed=Window]
 interface HTMLOptionElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
   [CEReactions, SetterThrows]
   attribute boolean disabled;
   readonly attribute HTMLFormElement? form;
diff --git a/dom/webidl/HTMLOutputElement.webidl b/dom/webidl/HTMLOutputElement.webidl
index 3fdac5ae083d..732ef5548a9b 100644
--- a/dom/webidl/HTMLOutputElement.webidl
+++ b/dom/webidl/HTMLOutputElement.webidl
@@ -12,9 +12,10 @@
  */
 
 // http://www.whatwg.org/specs/web-apps/current-work/#the-output-element
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLOutputElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
   [PutForwards=value, Constant]
   readonly attribute DOMTokenList htmlFor;
   readonly attribute HTMLFormElement? form;
diff --git a/dom/webidl/HTMLParagraphElement.webidl b/dom/webidl/HTMLParagraphElement.webidl
index 986ff02b0fd5..f5d0bfd36aba 100644
--- a/dom/webidl/HTMLParagraphElement.webidl
+++ b/dom/webidl/HTMLParagraphElement.webidl
@@ -12,9 +12,10 @@
  */
 
 // http://www.whatwg.org/specs/web-apps/current-work/#the-p-element
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLParagraphElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
 };
 
 // http://www.whatwg.org/specs/web-apps/current-work/#other-elements,-attributes-and-apis
diff --git a/dom/webidl/HTMLParamElement.webidl b/dom/webidl/HTMLParamElement.webidl
index 42738734dc8a..1fadfc6da6e4 100644
--- a/dom/webidl/HTMLParamElement.webidl
+++ b/dom/webidl/HTMLParamElement.webidl
@@ -13,9 +13,10 @@
  */
 
 // http://www.whatwg.org/specs/web-apps/current-work/#the-param-element
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLParamElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
            [CEReactions, SetterThrows, Pure]
            attribute DOMString name;
            [CEReactions, SetterThrows, Pure]
diff --git a/dom/webidl/HTMLPictureElement.webidl b/dom/webidl/HTMLPictureElement.webidl
index bbcfc2435ed9..520ff9e01199 100644
--- a/dom/webidl/HTMLPictureElement.webidl
+++ b/dom/webidl/HTMLPictureElement.webidl
@@ -4,7 +4,8 @@
  * You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLPictureElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
 };
diff --git a/dom/webidl/HTMLPreElement.webidl b/dom/webidl/HTMLPreElement.webidl
index bcb504014abf..f13fc8519532 100644
--- a/dom/webidl/HTMLPreElement.webidl
+++ b/dom/webidl/HTMLPreElement.webidl
@@ -12,9 +12,10 @@
  */
 
 // http://www.whatwg.org/specs/web-apps/current-work/#the-pre-element
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLPreElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
 };
 
 // http://www.whatwg.org/specs/web-apps/current-work/#other-elements,-attributes-and-apis
diff --git a/dom/webidl/HTMLProgressElement.webidl b/dom/webidl/HTMLProgressElement.webidl
index 5e02365e351d..e5326375ff36 100644
--- a/dom/webidl/HTMLProgressElement.webidl
+++ b/dom/webidl/HTMLProgressElement.webidl
@@ -11,9 +11,10 @@
  * and create derivative works of this document.
  */
 
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLProgressElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
            [CEReactions, SetterThrows]
            attribute double value;
            [CEReactions, SetterThrows]
diff --git a/dom/webidl/HTMLQuoteElement.webidl b/dom/webidl/HTMLQuoteElement.webidl
index 174de430e968..aaf3f3898556 100644
--- a/dom/webidl/HTMLQuoteElement.webidl
+++ b/dom/webidl/HTMLQuoteElement.webidl
@@ -12,9 +12,10 @@
  */
 
 // http://www.whatwg.org/specs/web-apps/current-work/#the-blockquote-element
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLQuoteElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
            [CEReactions, SetterThrows, Pure]
            attribute DOMString cite;
 };
diff --git a/dom/webidl/HTMLScriptElement.webidl b/dom/webidl/HTMLScriptElement.webidl
index 8284844f0735..a31e07b7b683 100644
--- a/dom/webidl/HTMLScriptElement.webidl
+++ b/dom/webidl/HTMLScriptElement.webidl
@@ -8,9 +8,10 @@
  * http://www.whatwg.org/specs/web-apps/current-work/#other-elements,-attributes-and-apis
  */
 
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLScriptElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
   [CEReactions, SetterNeedsSubjectPrincipal=NonSystem, SetterThrows]
   attribute DOMString src;
   [CEReactions, SetterThrows]
diff --git a/dom/webidl/HTMLSelectElement.webidl b/dom/webidl/HTMLSelectElement.webidl
index 567f2d2f3f25..0dd3d862247c 100644
--- a/dom/webidl/HTMLSelectElement.webidl
+++ b/dom/webidl/HTMLSelectElement.webidl
@@ -7,9 +7,10 @@
  * http://www.whatwg.org/html/#the-select-element
  */
 
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLSelectElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
   [CEReactions, SetterThrows, Pure]
   attribute boolean autofocus;
   [CEReactions, SetterThrows, Pure]
diff --git a/dom/webidl/HTMLSlotElement.webidl b/dom/webidl/HTMLSlotElement.webidl
index 1042d1243bd7..7488e398b95b 100644
--- a/dom/webidl/HTMLSlotElement.webidl
+++ b/dom/webidl/HTMLSlotElement.webidl
@@ -11,8 +11,10 @@
  * and create derivative works of this document.
  */
 
-[Exposed=Window, HTMLConstructor]
+[Exposed=Window]
 interface HTMLSlotElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
   [CEReactions, SetterThrows] attribute DOMString name;
   sequence<Node> assignedNodes(optional AssignedNodesOptions options = {});
   sequence<Element> assignedElements(optional AssignedNodesOptions options = {});
diff --git a/dom/webidl/HTMLSourceElement.webidl b/dom/webidl/HTMLSourceElement.webidl
index c0d7dde55dbc..e0fcdc4f521c 100644
--- a/dom/webidl/HTMLSourceElement.webidl
+++ b/dom/webidl/HTMLSourceElement.webidl
@@ -11,9 +11,10 @@
  * and create derivative works of this document.
  */
 
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLSourceElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
            [CEReactions, SetterNeedsSubjectPrincipal=NonSystem, SetterThrows]
            attribute DOMString src;
            [CEReactions, SetterThrows]
diff --git a/dom/webidl/HTMLSpanElement.webidl b/dom/webidl/HTMLSpanElement.webidl
index 314ff5b3e556..b8c723bd3f6c 100644
--- a/dom/webidl/HTMLSpanElement.webidl
+++ b/dom/webidl/HTMLSpanElement.webidl
@@ -12,6 +12,7 @@
  */
 
 // http://www.whatwg.org/specs/web-apps/current-work/#the-span-element
-[HTMLConstructor,
- Exposed=Window]
-interface HTMLSpanElement : HTMLElement {};
+[Exposed=Window]
+interface HTMLSpanElement : HTMLElement {
+  [HTMLConstructor] constructor();
+};
diff --git a/dom/webidl/HTMLStyleElement.webidl b/dom/webidl/HTMLStyleElement.webidl
index f047f783257a..8720a671d3fd 100644
--- a/dom/webidl/HTMLStyleElement.webidl
+++ b/dom/webidl/HTMLStyleElement.webidl
@@ -8,9 +8,10 @@
  * http://www.whatwg.org/specs/web-apps/current-work/#other-elements,-attributes-and-apis
  */
 
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLStyleElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
            [Pure]
            attribute boolean disabled;
            [CEReactions, SetterThrows, Pure]
diff --git a/dom/webidl/HTMLTableCaptionElement.webidl b/dom/webidl/HTMLTableCaptionElement.webidl
index 133a61fcc380..6112fe6f310d 100644
--- a/dom/webidl/HTMLTableCaptionElement.webidl
+++ b/dom/webidl/HTMLTableCaptionElement.webidl
@@ -11,9 +11,10 @@
  * and create derivative works of this document.
  */
 
-[HTMLConstructor,
- Exposed=Window]
-interface HTMLTableCaptionElement : HTMLElement {};
+[Exposed=Window]
+interface HTMLTableCaptionElement : HTMLElement {
+  [HTMLConstructor] constructor();
+};
 
 partial interface HTMLTableCaptionElement {
            [CEReactions, SetterThrows]
diff --git a/dom/webidl/HTMLTableCellElement.webidl b/dom/webidl/HTMLTableCellElement.webidl
index 8f3247459c37..041e798b8318 100644
--- a/dom/webidl/HTMLTableCellElement.webidl
+++ b/dom/webidl/HTMLTableCellElement.webidl
@@ -11,9 +11,10 @@
  * and create derivative works of this document.
  */
 
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLTableCellElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
            [CEReactions, SetterThrows]
            attribute unsigned long colSpan;
            [CEReactions, SetterThrows]
diff --git a/dom/webidl/HTMLTableColElement.webidl b/dom/webidl/HTMLTableColElement.webidl
index 0a977e618760..c17a78c92545 100644
--- a/dom/webidl/HTMLTableColElement.webidl
+++ b/dom/webidl/HTMLTableColElement.webidl
@@ -11,9 +11,10 @@
  * and create derivative works of this document.
  */
 
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLTableColElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
            [CEReactions, SetterThrows]
            attribute unsigned long span;
 };
diff --git a/dom/webidl/HTMLTableElement.webidl b/dom/webidl/HTMLTableElement.webidl
index 3362b8e41f3f..343f0f701890 100644
--- a/dom/webidl/HTMLTableElement.webidl
+++ b/dom/webidl/HTMLTableElement.webidl
@@ -11,9 +11,10 @@
  * and create derivative works of this document.
  */
 
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLTableElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
            [CEReactions, SetterThrows]
            attribute HTMLTableCaptionElement? caption;
   HTMLElement createCaption();
diff --git a/dom/webidl/HTMLTableRowElement.webidl b/dom/webidl/HTMLTableRowElement.webidl
index a851baf67646..a8f455c7fdb9 100644
--- a/dom/webidl/HTMLTableRowElement.webidl
+++ b/dom/webidl/HTMLTableRowElement.webidl
@@ -11,9 +11,10 @@
  * and create derivative works of this document.
  */
 
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLTableRowElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
   readonly attribute long rowIndex;
   readonly attribute long sectionRowIndex;
   readonly attribute HTMLCollection cells;
diff --git a/dom/webidl/HTMLTableSectionElement.webidl b/dom/webidl/HTMLTableSectionElement.webidl
index 2adb75a47733..0724492926bb 100644
--- a/dom/webidl/HTMLTableSectionElement.webidl
+++ b/dom/webidl/HTMLTableSectionElement.webidl
@@ -11,9 +11,10 @@
  * and create derivative works of this document.
  */
 
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLTableSectionElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
   readonly attribute HTMLCollection rows;
   [Throws]
   HTMLElement insertRow(optional long index = -1);
diff --git a/dom/webidl/HTMLTemplateElement.webidl b/dom/webidl/HTMLTemplateElement.webidl
index ccb13151dca1..3728e986e543 100644
--- a/dom/webidl/HTMLTemplateElement.webidl
+++ b/dom/webidl/HTMLTemplateElement.webidl
@@ -9,9 +9,10 @@
  * liability, trademark and document use rules apply.
  */
 
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLTemplateElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
     readonly attribute DocumentFragment content;
 };
 
diff --git a/dom/webidl/HTMLTextAreaElement.webidl b/dom/webidl/HTMLTextAreaElement.webidl
index a48b1ab40a21..f66818c37285 100644
--- a/dom/webidl/HTMLTextAreaElement.webidl
+++ b/dom/webidl/HTMLTextAreaElement.webidl
@@ -14,9 +14,10 @@
 interface nsIEditor;
 interface XULControllers;
 
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLTextAreaElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
   [CEReactions, SetterThrows, Pure]
            attribute DOMString autocomplete;
   [CEReactions, SetterThrows, Pure]
diff --git a/dom/webidl/HTMLTimeElement.webidl b/dom/webidl/HTMLTimeElement.webidl
index 10b9fd37697d..3f0d8733ebce 100644
--- a/dom/webidl/HTMLTimeElement.webidl
+++ b/dom/webidl/HTMLTimeElement.webidl
@@ -7,9 +7,10 @@
  * http://www.whatwg.org/specs/web-apps/current-work/multipage/text-level-semantics.html#the-time-element
  */
 
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLTimeElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
            [CEReactions, SetterThrows]
            attribute DOMString dateTime;
 };
diff --git a/dom/webidl/HTMLTitleElement.webidl b/dom/webidl/HTMLTitleElement.webidl
index fbc9e4455371..25f4b9fbef7b 100644
--- a/dom/webidl/HTMLTitleElement.webidl
+++ b/dom/webidl/HTMLTitleElement.webidl
@@ -7,9 +7,10 @@
  * http://www.whatwg.org/specs/web-apps/current-work/#the-title-element
  */
 
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLTitleElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
            [CEReactions, Throws]
            attribute DOMString text;
 };
diff --git a/dom/webidl/HTMLTrackElement.webidl b/dom/webidl/HTMLTrackElement.webidl
index 4ebb77678587..67558f6cbcf8 100644
--- a/dom/webidl/HTMLTrackElement.webidl
+++ b/dom/webidl/HTMLTrackElement.webidl
@@ -7,9 +7,10 @@
  * http://www.whatwg.org/specs/web-apps/current-work/#the-track-element
  */
 
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLTrackElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
   [CEReactions, SetterThrows, Pure]
   attribute DOMString kind;
   [CEReactions, SetterThrows, Pure]
diff --git a/dom/webidl/HTMLUListElement.webidl b/dom/webidl/HTMLUListElement.webidl
index 962ea6f71e29..447524c48cef 100644
--- a/dom/webidl/HTMLUListElement.webidl
+++ b/dom/webidl/HTMLUListElement.webidl
@@ -13,9 +13,10 @@
  */
 
 // http://www.whatwg.org/specs/web-apps/current-work/#the-ul-element
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLUListElement : HTMLElement {
+  [HTMLConstructor] constructor();
+
 };
 
 // http://www.whatwg.org/specs/web-apps/current-work/#other-elements,-attributes-and-apis
diff --git a/dom/webidl/HTMLVideoElement.webidl b/dom/webidl/HTMLVideoElement.webidl
index 2db15aa3553a..d5555feb108e 100644
--- a/dom/webidl/HTMLVideoElement.webidl
+++ b/dom/webidl/HTMLVideoElement.webidl
@@ -11,9 +11,10 @@
  * and create derivative works of this document.
  */
 
-[HTMLConstructor,
- Exposed=Window]
+[Exposed=Window]
 interface HTMLVideoElement : HTMLMediaElement {
+  [HTMLConstructor] constructor();
+
   [CEReactions, SetterThrows]
            attribute unsigned long width;
   [CEReactions, SetterThrows]
diff --git a/dom/webidl/XULElement.webidl b/dom/webidl/XULElement.webidl
index 0e09cf6cebf1..8292ea1445a9 100644
--- a/dom/webidl/XULElement.webidl
+++ b/dom/webidl/XULElement.webidl
@@ -6,9 +6,11 @@
 
 interface XULControllers;
 
-[HTMLConstructor, Func="IsChromeOrXBL",
+[Func="IsChromeOrXBL",
  Exposed=Window]
 interface XULElement : Element {
+  [HTMLConstructor] constructor();
+
   // Layout properties
   [SetterThrows]
   attribute DOMString align;
diff --git a/dom/webidl/XULPopupElement.webidl b/dom/webidl/XULPopupElement.webidl
index 9749eee2d18c..b42934bfea79 100644
--- a/dom/webidl/XULPopupElement.webidl
+++ b/dom/webidl/XULPopupElement.webidl
@@ -20,10 +20,12 @@ dictionary OpenPopupOptions {
 
 typedef (DOMString or OpenPopupOptions) StringOrOpenPopupOptions;
 
-[HTMLConstructor, Func="IsChromeOrXBL",
+[Func="IsChromeOrXBL",
  Exposed=Window]
 interface XULPopupElement : XULElement
 {
+  [HTMLConstructor] constructor();
+
   /**
    * Allow the popup to automatically position itself.
    */