--- a/dom/html/nsGenericHTMLElement.cpp
+++ b/dom/html/nsGenericHTMLElement.cpp
@@ -117,16 +117,34 @@ static const nsAttrValue::EnumTable kInp
     {"tel", NS_INPUTMODE_TEL},
     {"url", NS_INPUTMODE_URL},
     {"email", NS_INPUTMODE_EMAIL},
     {"numeric", NS_INPUTMODE_NUMERIC},
     {"decimal", NS_INPUTMODE_DECIMAL},
     {"search", NS_INPUTMODE_SEARCH},
     {nullptr, 0}};
 
+static const uint8_t NS_ENTERKEYHINT_ENTER = 1;
+static const uint8_t NS_ENTERKEYHINT_DONE = 2;
+static const uint8_t NS_ENTERKEYHINT_GO = 3;
+static const uint8_t NS_ENTERKEYHINT_NEXT = 4;
+static const uint8_t NS_ENTERKEYHINT_PREVIOUS = 5;
+static const uint8_t NS_ENTERKEYHINT_SEARCH = 6;
+static const uint8_t NS_ENTERKEYHINT_SEND = 7;
+
+static const nsAttrValue::EnumTable kEnterKeyHintTable[] = {
+    {"enter", NS_ENTERKEYHINT_ENTER},
+    {"done", NS_ENTERKEYHINT_DONE},
+    {"go", NS_ENTERKEYHINT_GO},
+    {"next", NS_ENTERKEYHINT_NEXT},
+    {"previous", NS_ENTERKEYHINT_PREVIOUS},
+    {"search", NS_ENTERKEYHINT_SEARCH},
+    {"send", NS_ENTERKEYHINT_SEND},
+    {nullptr, 0}};
+
 nsresult nsGenericHTMLElement::CopyInnerTo(Element* aDst) {
   MOZ_ASSERT(!aDst->GetUncomposedDoc(),
              "Should not CopyInnerTo an Element in a document");
 
   auto reparse = aDst->OwnerDoc() == OwnerDoc() ? ReparseAttributes::No
                                                 : ReparseAttributes::Yes;
   nsresult rv = Element::CopyInnerTo(aDst, reparse);
   NS_ENSURE_SUCCESS(rv, rv);
@@ -852,16 +870,20 @@ bool nsGenericHTMLElement::ParseAttribut
     if (aAttribute == nsGkAtoms::rel) {
       aResult.ParseAtomArray(aValue);
       return true;
     }
 
     if (aAttribute == nsGkAtoms::inputmode) {
       return aResult.ParseEnumValue(aValue, kInputmodeTable, false);
     }
+
+    if (aAttribute == nsGkAtoms::enterkeyhint) {
+      return aResult.ParseEnumValue(aValue, kEnterKeyHintTable, false);
+    }
   }
 
   return nsGenericHTMLElementBase::ParseAttribute(
       aNamespaceID, aAttribute, aValue, aMaybeScriptedPrincipal, aResult);
 }
 
 bool nsGenericHTMLElement::ParseBackgroundAttribute(int32_t aNamespaceID,
                                                     nsAtom* aAttribute,

--- a/dom/html/nsGenericHTMLElement.h
+++ b/dom/html/nsGenericHTMLElement.h
@@ -175,16 +175,23 @@ class nsGenericHTMLElement : public nsGe
 
   void GetInputMode(nsAString& aValue) {
     GetEnumAttr(nsGkAtoms::inputmode, nullptr, aValue);
   }
   void SetInputMode(const nsAString& aValue, ErrorResult& aRv) {
     SetHTMLAttr(nsGkAtoms::inputmode, aValue, aRv);
   }
 
+  void GetEnterKeyHint(nsAString& aValue) {
+    GetEnumAttr(nsGkAtoms::enterkeyhint, nullptr, aValue);
+  }
+  void SetEnterKeyHint(const nsAString& aValue, ErrorResult& aRv) {
+    SetHTMLAttr(nsGkAtoms::enterkeyhint, aValue, aRv);
+  }
+
   /**
    * Determine whether an attribute is an event (onclick, etc.)
    * @param aName the attribute
    * @return whether the name is an event handler name
    */
   virtual bool IsEventAttributeNameInternal(nsAtom* aName) override;
 
 #define EVENT(name_, id_, type_, struct_) /* nothing; handled by nsINode */

--- a/dom/webidl/HTMLElement.webidl
+++ b/dom/webidl/HTMLElement.webidl
@@ -47,16 +47,18 @@ interface HTMLElement : Element {
   [Pure]
   readonly attribute HTMLMenuElement? contextMenu;
   //[SetterThrows]
   //         attribute HTMLMenuElement? contextMenu;
   [CEReactions, SetterThrows, Pure]
            attribute boolean spellcheck;
   [CEReactions, Pure, SetterThrows, Pref="dom.forms.inputmode"]
            attribute DOMString inputMode;
+  [CEReactions, Pure, SetterThrows, Pref="dom.forms.enterkeyhint"]
+           attribute DOMString enterKeyHint;
 
   attribute DOMString nonce;
 
   // command API
   //readonly attribute DOMString? commandType;
   //readonly attribute DOMString? commandLabel;
   //readonly attribute DOMString? commandIcon;
   //readonly attribute boolean? commandHidden;

--- a/modules/libpref/init/StaticPrefList.yaml
+++ b/modules/libpref/init/StaticPrefList.yaml
@@ -2021,16 +2021,22 @@
 
 # Support for input type=month, type=week and type=datetime-local. By default,
 # disabled.
 - name: dom.forms.datetime.others
   type: bool
   value: @IS_ANDROID@
   mirror: always
 
+# Is support for HTMLElement.enterKeyHint enabled?
+- name: dom.forms.enterkeyhint
+  type: bool
+  value: @IS_NIGHTLY_BUILD@
+  mirror: always
+
 # Is support for HTMLElement.inputMode enabled?
 - name: dom.forms.inputmode
   type: bool
 #if defined(ANDROID)
   value: true
 #else
   value: @IS_NOT_RELEASE_OR_BETA@
 #endif

--- a/testing/web-platform/meta/html/dom/idlharness.https.html.ini
+++ b/testing/web-platform/meta/html/dom/idlharness.https.html.ini
@@ -1,9 +1,9 @@
-prefs: [dom.security.featurePolicy.enabled:true, dom.security.featurePolicy.experimental.enabled:true, dom.security.featurePolicy.header.enabled:true, dom.security.featurePolicy.webidl.enabled:true, dom.webcomponents.elementInternals.enabled:true, dom.forms.requestsubmit.enabled:true, dom.forms.inputmode:true]
+prefs: [dom.security.featurePolicy.enabled:true, dom.security.featurePolicy.experimental.enabled:true, dom.security.featurePolicy.header.enabled:true, dom.security.featurePolicy.webidl.enabled:true, dom.webcomponents.elementInternals.enabled:true, dom.forms.requestsubmit.enabled:true, dom.forms.inputmode:true, dom.forms.enterkeyhint:true]
 [idlharness.https.html?exclude=(Document|Window|HTML.*)]
   [OffscreenCanvasRenderingContext2D interface: operation lineTo(unrestricted double, unrestricted double)]
     expected: FAIL
 
   [OffscreenCanvasRenderingContext2D interface: attribute globalAlpha]
     expected: FAIL
 
   [AudioTrack interface: existence and properties of interface prototype object]
@@ -880,19 +880,16 @@ prefs: [dom.security.featurePolicy.enabl
     expected: FAIL
 
   [HTMLDialogElement interface: operation show()]
     expected: FAIL
 
   [HTMLInputElement interface: createInput("search") must inherit property "dirName" with the proper type]
     expected: FAIL
 
-  [HTMLElement interface: attribute enterKeyHint]
-    expected: FAIL
-
   [HTMLInputElement interface: createInput("checkbox") must inherit property "dirName" with the proper type]
     expected: FAIL
 
   [HTMLFormElement interface: attribute relList]
     expected: FAIL
 
   [HTMLDialogElement interface: existence and properties of interface prototype object]
     expected: FAIL
@@ -937,19 +934,16 @@ prefs: [dom.security.featurePolicy.enabl
     expected: FAIL
 
   [HTMLInputElement interface: createInput("password") must inherit property "dirName" with the proper type]
     expected: FAIL
 
   [HTMLInputElement interface: document.createElement("input") must inherit property "dirName" with the proper type]
     expected: FAIL
 
-  [HTMLElement interface: document.createElement("noscript") must inherit property "enterKeyHint" with the proper type]
-    expected: FAIL
-
   [HTMLMediaElement interface: new Audio() must inherit property "videoTracks" with the proper type]
     expected: FAIL
 
   [HTMLDialogElement interface: existence and properties of interface prototype object's "constructor" property]
     expected: FAIL
 
   [HTMLMediaElement interface: attribute videoTracks]
     expected: FAIL

--- a/testing/web-platform/meta/html/dom/reflection-misc.html.ini
+++ b/testing/web-platform/meta/html/dom/reflection-misc.html.ini
@@ -1,10 +1,10 @@
 [reflection-misc.html]
-  prefs: [dom.dialog_element.enabled:true, dom.forms.inputmode:true]
+  prefs: [dom.dialog_element.enabled:true, dom.forms.inputmode:true, dom.forms.enterkeyhint:true]
   [script.nonce: IDL set to ""]
     expected: FAIL
 
   [script.nonce: IDL set to " \\0\\x01\\x02\\x03\\x04\\x05\\x06\\x07 \\b\\t\\n\\v\\f\\r\\x0e\\x0f \\x10\\x11\\x12\\x13\\x14\\x15\\x16\\x17 \\x18\\x19\\x1a\\x1b\\x1c\\x1d\\x1e\\x1f  foo "]
     expected: FAIL
 
   [script.nonce: IDL set to undefined]
     expected: FAIL
@@ -46,340 +46,16 @@
     expected: FAIL
 
   [script.nonce: IDL set to null]
     expected: FAIL
 
   [script.nonce: IDL set to object "test-toString"]
     expected: FAIL
 
-  [undefinedelement.enterKeyHint: IDL set to "send\\0"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to null]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to ""]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to true]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "go"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "o"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "revious"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to null]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "go\\0"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "nter"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "xgo"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "next"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to Infinity]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to object "test-valueOf"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "enter"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to NaN]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "ENTER"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "NEXT"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "SEARCH"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "xgo"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "next\\0"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "DONE"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to Infinity]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "send"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "enter\\0"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "done\\0"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "PREVIOUS"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "nter"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "GO"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "search"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "NEXT"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "next\\0"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "xsend"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "\\0"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "SEARCH"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "done"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "ext"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "previous\\0"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "xsearch"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "xenter"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "SEND"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to false]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "GO"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "send"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "xprevious"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to object "test-valueOf"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "PREVIOUS"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to undefined]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "enter\\0"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "earch"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to " \\0\\x01\\x02\\x03\\x04\\x05\\x06\\x07 \\b\\t\\n\\v\\f\\r\\x0e\\x0f \\x10\\x11\\x12\\x13\\x14\\x15\\x16\\x17 \\x18\\x19\\x1a\\x1b\\x1c\\x1d\\x1e\\x1f  foo "]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to ""]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "go"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "search\\0"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to -Infinity]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to undefined]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "send\\0"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to 7]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "\\0"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "done\\0"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "end"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "ENTER"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "previous"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "xsend"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL get with DOM attribute unset]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "SEND"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "previous"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "xprevious"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to 1.5]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "5%"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "+100"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to ".5"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to 1.5]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "5%"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "+100"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to ".5"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "next"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to -Infinity]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to " \\0\\x01\\x02\\x03\\x04\\x05\\x06\\x07 \\b\\t\\n\\v\\f\\r\\x0e\\x0f \\x10\\x11\\x12\\x13\\x14\\x15\\x16\\x17 \\x18\\x19\\x1a\\x1b\\x1c\\x1d\\x1e\\x1f  foo "]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "one"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "earch"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "xnext"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "xnext"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "enter"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "xdone"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "DONE"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "o"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "xsearch"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "search\\0"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "end"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to false]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "one"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "xenter"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "go\\0"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to true]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "ext"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "search"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to object "test-toString"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to 7]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "xdone"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to object "[object Object\]"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to object "[object Object\]"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to object "test-toString"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to NaN]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "previous\\0"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: typeof IDL attribute]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "done"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "revious"]
-    expected: FAIL
-
   [script.autofocus: setAttribute() to NaN]
     expected: FAIL
 
   [undefinedelement.autofocus: setAttribute() to "5%"]
     expected: FAIL
 
   [details.autofocus: setAttribute() to "\\0"]
     expected: FAIL
@@ -1737,27 +1413,8 @@
   [html.autofocus: IDL set to " foo "]
     expected: FAIL
 
   [script.autofocus: IDL set to object "test-valueOf"]
     expected: FAIL
 
   [summary.autofocus: typeof IDL attribute]
     expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "previouſ"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "ſearch"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: IDL set to "ſend"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "ſend"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "ſearch"]
-    expected: FAIL
-
-  [undefinedelement.enterKeyHint: setAttribute() to "previouſ"]
-    expected: FAIL
-

--- a/xpcom/ds/StaticAtoms.py
+++ b/xpcom/ds/StaticAtoms.py
@@ -405,16 +405,17 @@ STATIC_ATOMS = [
     Atom("elements", "elements"),
     Atom("em", "em"),
     Atom("embed", "embed"),
     Atom("empty", "empty"),
     Atom("encoding", "encoding"),
     Atom("enctype", "enctype"),
     Atom("end", "end"),
     Atom("endEvent", "endEvent"),
+    Atom("enterkeyhint", "enterkeyhint"),
     Atom("equalsize", "equalsize"),
     Atom("error", "error"),
     Atom("ethiopic_numeric", "ethiopic-numeric"),
     Atom("even", "even"),
     Atom("event", "event"),
     Atom("events", "events"),
     Atom("excludeResultPrefixes", "exclude-result-prefixes"),
     Atom("exportparts", "exportparts"),