diff --git a/dom/base/Element.cpp b/dom/base/Element.cpp
index 364022644d..a381f0a5a2 100644
--- a/dom/base/Element.cpp
+++ b/dom/base/Element.cpp
@@ -308,12 +308,18 @@ Element::TabIndex()
 }
 
 void
-Element::Focus(mozilla::ErrorResult& aError)
+Element::Focus(const FocusOptions& aOptions, ErrorResult& aError)
 {
   nsCOMPtr<nsIDOMElement> domElement = do_QueryInterface(this);
   nsIFocusManager* fm = nsFocusManager::GetFocusManager();
+  // Also other browsers seem to have the hack to not re-focus (and flush) when
+  // the element is already focused.
+  // Until https://github.com/whatwg/html/issues/4512 is clarified, we'll
+  // maintain interoperatibility by not re-focusing, independent of aOptions.
+  // I.e., `focus({ preventScroll: true})` followed by `focus( { preventScroll:
+  // false })` won't re-focus.
   if (fm && domElement) {
-    aError = fm->SetFocus(domElement, 0);
+    aError = fm->SetFocus(domElement, nsFocusManager::FocusOptionsToFocusManagerFlags(aOptions));
   }
 }
 
diff --git a/dom/base/Element.h b/dom/base/Element.h
index 14c53ae465..2f1d449281 100644
--- a/dom/base/Element.h
+++ b/dom/base/Element.h
@@ -216,7 +216,7 @@ public:
   /**
    * Make focus on this element.
    */
-  virtual void Focus(mozilla::ErrorResult& aError);
+  virtual void Focus(const FocusOptions& aOptions, ErrorResult& aError);
 
   /**
    * Show blur and clear focus.
diff --git a/dom/base/nsFocusManager.cpp b/dom/base/nsFocusManager.cpp
index fa321ac300..f8d265e905 100644
--- a/dom/base/nsFocusManager.cpp
+++ b/dom/base/nsFocusManager.cpp
@@ -48,6 +48,7 @@
 
 #include "mozilla/ContentEvents.h"
 #include "mozilla/dom/Element.h"
+#include "mozilla/dom/ElementBinding.h"
 #include "mozilla/dom/ShadowRoot.h"
 #include "mozilla/dom/HTMLInputElement.h"
 #include "mozilla/dom/HTMLSlotElement.h"
@@ -3005,6 +3006,11 @@ nsFocusManager::DetermineElementToMoveFocus(nsPIDOMWindowOuter* aWindow,
   return NS_OK;
 }
 
+uint32_t nsFocusManager::FocusOptionsToFocusManagerFlags(
+    const mozilla::dom::FocusOptions& aOptions) {
+  return aOptions.mPreventScroll ? nsIFocusManager::FLAG_NOSCROLL : 0;
+}
+
 static bool
 IsHostOrSlot(nsIContent* aContent)
 {
diff --git a/dom/base/nsFocusManager.h b/dom/base/nsFocusManager.h
index 8fe919a155..b05df8abf1 100644
--- a/dom/base/nsFocusManager.h
+++ b/dom/base/nsFocusManager.h
@@ -26,6 +26,7 @@ class nsIMessageBroadcaster;
 
 namespace mozilla {
 namespace dom {
+struct FocusOptions;
 class TabParent;
 }
 }
@@ -110,6 +111,9 @@ public:
   static nsIContent* GetFocusedDescendant(nsPIDOMWindowOuter* aWindow, bool aDeep,
                                           nsPIDOMWindowOuter** aFocusedWindow);
 
+  static uint32_t FocusOptionsToFocusManagerFlags(
+      const mozilla::dom::FocusOptions& aOptions);
+
   /**
    * Returns the content node that focus will be redirected to if aContent was
    * focused. This is used for the special case of certain XUL elements such
diff --git a/dom/html/HTMLInputElement.cpp b/dom/html/HTMLInputElement.cpp
index 56b7c36da2..0e20834fe8 100644
--- a/dom/html/HTMLInputElement.cpp
+++ b/dom/html/HTMLInputElement.cpp
@@ -3590,7 +3590,7 @@ HTMLInputElement::Blur(ErrorResult& aError)
 } 
 
 void
-HTMLInputElement::Focus(ErrorResult& aError)
+HTMLInputElement::Focus(const FocusOptions& aOptions, ErrorResult& aError)
 {
   if (mType == NS_FORM_INPUT_NUMBER) {
     // Focus our anonymous text control, if we have one.
@@ -3600,7 +3600,7 @@ HTMLInputElement::Focus(ErrorResult& aError)
       RefPtr<HTMLInputElement> textControl =
         numberControlFrame->GetAnonTextControl();
       if (textControl) {
-        textControl->Focus(aError);
+        textControl->Focus(aOptions, aError);
         return;
       }
     }
@@ -3616,7 +3616,7 @@ HTMLInputElement::Focus(ErrorResult& aError)
   }
 
   if (mType != NS_FORM_INPUT_FILE) {
-    nsGenericHTMLElement::Focus(aError);
+    nsGenericHTMLElement::Focus(aOptions, aError);
     return;
   }
 
diff --git a/dom/html/HTMLInputElement.h b/dom/html/HTMLInputElement.h
index 462d29b524..9c73d10b1c 100644
--- a/dom/html/HTMLInputElement.h
+++ b/dom/html/HTMLInputElement.h
@@ -134,7 +134,8 @@ public:
   virtual int32_t TabIndexDefault() override;
   using nsGenericHTMLElement::Focus;
   virtual void Blur(ErrorResult& aError) override;
-  virtual void Focus(ErrorResult& aError) override;
+  virtual void Focus(const FocusOptions& aOptions,
+                     ErrorResult& aError) override;
 
   // nsINode
 #if !defined(ANDROID) && !defined(XP_MACOSX)
diff --git a/dom/html/HTMLLabelElement.cpp b/dom/html/HTMLLabelElement.cpp
index 00df4b5d94..46858e4ce1 100644
--- a/dom/html/HTMLLabelElement.cpp
+++ b/dom/html/HTMLLabelElement.cpp
@@ -93,14 +93,15 @@ HTMLLabelElement::GetForm() const
 }
 
 void
-HTMLLabelElement::Focus(ErrorResult& aError)
+HTMLLabelElement::Focus(const FocusOptions& aOptions,
+                        ErrorResult& aError)
 {
   // retarget the focus method at the for content
   nsIFocusManager* fm = nsFocusManager::GetFocusManager();
   if (fm) {
     nsCOMPtr<nsIDOMElement> elem = do_QueryObject(GetLabeledElement());
     if (elem)
-      fm->SetFocus(elem, 0);
+      fm->SetFocus(elem, nsFocusManager::FocusOptionsToFocusManagerFlags(aOptions));
   }
 }
 
diff --git a/dom/html/HTMLLabelElement.h b/dom/html/HTMLLabelElement.h
index 5771a001f7..29a71b0837 100644
--- a/dom/html/HTMLLabelElement.h
+++ b/dom/html/HTMLLabelElement.h
@@ -56,7 +56,8 @@ public:
   }
 
   using nsGenericHTMLElement::Focus;
-  virtual void Focus(mozilla::ErrorResult& aError) override;
+  virtual void Focus(const FocusOptions& aOptions,
+                     ErrorResult& aError) override;
 
   virtual bool IsDisabled() const override { return false; }
 
diff --git a/dom/html/HTMLLegendElement.cpp b/dom/html/HTMLLegendElement.cpp
index 87df3ba3e7..73038e38b1 100644
--- a/dom/html/HTMLLegendElement.cpp
+++ b/dom/html/HTMLLegendElement.cpp
@@ -86,7 +86,8 @@ HTMLLegendElement::UnbindFromTree(bool aDeep, bool aNullParent)
 }
 
 void
-HTMLLegendElement::Focus(ErrorResult& aError)
+HTMLLegendElement::Focus(const FocusOptions& aOptions,
+                         ErrorResult& aError)
 {
   nsIFrame* frame = GetPrimaryFrame();
   if (!frame) {
@@ -95,7 +96,7 @@ HTMLLegendElement::Focus(ErrorResult& aError)
 
   int32_t tabIndex;
   if (frame->IsFocusable(&tabIndex, false)) {
-    nsGenericHTMLElement::Focus(aError);
+    nsGenericHTMLElement::Focus(aOptions, aError);
     return;
   }
 
@@ -108,7 +109,8 @@ HTMLLegendElement::Focus(ErrorResult& aError)
 
   nsCOMPtr<nsIDOMElement> result;
   aError = fm->MoveFocus(nullptr, this, nsIFocusManager::MOVEFOCUS_FORWARD,
-                         nsIFocusManager::FLAG_NOPARENTFRAME,
+                         nsIFocusManager::FLAG_NOPARENTFRAME |
+                         nsFocusManager::FocusOptionsToFocusManagerFlags(aOptions),
                          getter_AddRefs(result));
 }
 
@@ -116,9 +118,10 @@ bool
 HTMLLegendElement::PerformAccesskey(bool aKeyCausesActivation,
                                     bool aIsTrustedEvent)
 {
-  // just use the same behaviour as the focus method
+  FocusOptions options;
   ErrorResult rv;
-  Focus(rv);
+
+  Focus(options, rv);
   return NS_SUCCEEDED(rv.StealNSResult());
 }
 
diff --git a/dom/html/HTMLLegendElement.h b/dom/html/HTMLLegendElement.h
index 6ce3140ec9..79b585edae 100644
--- a/dom/html/HTMLLegendElement.h
+++ b/dom/html/HTMLLegendElement.h
@@ -24,7 +24,8 @@ public:
   NS_IMPL_FROMCONTENT_HTML_WITH_TAG(HTMLLegendElement, legend)
 
   using nsGenericHTMLElement::Focus;
-  virtual void Focus(ErrorResult& aError) override;
+  virtual void Focus(const FocusOptions& aOptions,
+                     ErrorResult& aError) override;
 
   virtual bool PerformAccesskey(bool aKeyCausesActivation,
                                 bool aIsTrustedEvent) override;
diff --git a/dom/html/nsGenericHTMLElement.cpp b/dom/html/nsGenericHTMLElement.cpp
index 997decd7a0..ba9db1febd 100644
--- a/dom/html/nsGenericHTMLElement.cpp
+++ b/dom/html/nsGenericHTMLElement.cpp
@@ -150,8 +150,9 @@ public:
     // If something is focused in the same document, ignore autofocus.
     if (!fm->GetFocusedContent() ||
         fm->GetFocusedContent()->OwnerDoc() != document) {
-      mozilla::ErrorResult rv;
-      mElement->Focus(rv);
+      FocusOptions options;
+      ErrorResult rv;
+      mElement->Focus(options, rv);
       return rv.StealNSResult();
     }
 
diff --git a/dom/html/nsGenericHTMLElement.h b/dom/html/nsGenericHTMLElement.h
index 5807c1746d..cd1bf59069 100644
--- a/dom/html/nsGenericHTMLElement.h
+++ b/dom/html/nsGenericHTMLElement.h
@@ -434,8 +434,9 @@ public:
     return rv.StealNSResult();
   }
   NS_IMETHOD Focus() final override {
+    mozilla::dom::FocusOptions options;
     mozilla::ErrorResult rv;
-    Focus(rv);
+    Focus(options, rv);
     return rv.StealNSResult();
   }
   NS_IMETHOD GetDraggable(bool* aDraggable) final override {
diff --git a/dom/mathml/MathMLElement.cpp b/dom/mathml/MathMLElement.cpp
index e453741450..17eb7b5bfd 100644
--- a/dom/mathml/MathMLElement.cpp
+++ b/dom/mathml/MathMLElement.cpp
@@ -435,8 +435,7 @@ MathMLElement::ParseNumericValue(const nsString& aString,
     number.Append(c);
   }
 
-  if (/*StaticPrefs::mathml_legacy_number_syntax_disabled() &&*/ gotDot &&
-      str[i - 1] == '.') {
+  if (gotDot && str[i - 1] == '.') {
     if (!(aFlags & PARSE_SUPPRESS_WARNINGS)) {
       ReportLengthParseError(aString, aDocument);
     }
diff --git a/dom/webidl/Element.webidl b/dom/webidl/Element.webidl
index ab62440f6f..4e239e5fe7 100644
--- a/dom/webidl/Element.webidl
+++ b/dom/webidl/Element.webidl
@@ -169,6 +169,23 @@ interface mixin ElementCSSInlineStyle {
   readonly attribute CSSStyleDeclaration style;
 };
 
+// https://html.spec.whatwg.org/#focus-management-apis
+dictionary FocusOptions {
+  boolean preventScroll = false;
+};
+
+interface mixin HTMLOrForeignElement {
+  [SameObject] readonly attribute DOMStringMap dataset;
+  // See bug 1389421
+  // attribute DOMString nonce; // intentionally no [CEReactions]
+
+  // See bug 1575154
+  // [CEReactions] attribute boolean autofocus;
+  [CEReactions, SetterThrows, Pure] attribute long tabIndex;
+  [Throws] void focus(optional FocusOptions options);
+  [Throws] void blur();
+};
+
 // http://dev.w3.org/csswg/cssom-view/
 enum ScrollLogicalPosition { "start", "center", "end", "nearest" };
 dictionary ScrollIntoViewOptions : ScrollOptions {
diff --git a/dom/webidl/HTMLElement.webidl b/dom/webidl/HTMLElement.webidl
index ee98607388..31046fabdb 100644
--- a/dom/webidl/HTMLElement.webidl
+++ b/dom/webidl/HTMLElement.webidl
@@ -22,8 +22,6 @@ interface HTMLElement : Element {
   //         attribute boolean translate;
   [CEReactions, SetterThrows, Pure]
            attribute DOMString dir;
-  [Constant]
-  readonly attribute DOMStringMap dataset;
 
   [CEReactions, GetterThrows, Pure]
            attribute [TreatNullAs=EmptyString] DOMString innerText;
@@ -32,12 +30,6 @@ interface HTMLElement : Element {
   [CEReactions, SetterThrows, Pure]
            attribute boolean hidden;
   void click();
-  [CEReactions, SetterThrows, Pure]
-           attribute long tabIndex;
-  [Throws]
-  void focus();
-  [Throws]
-  void blur();
   [CEReactions, SetterThrows, Pure]
            attribute DOMString accessKey;
   [Pure]
@@ -92,6 +84,7 @@ interface mixin TouchEventHandlers {
 };
 
 HTMLElement includes GlobalEventHandlers;
+HTMLElement includes HTMLOrForeignElement;
 HTMLElement includes DocumentAndElementEventHandlers;
 HTMLElement includes ElementCSSInlineStyle;
 HTMLElement includes TouchEventHandlers;
diff --git a/dom/webidl/MathMLElement.webidl b/dom/webidl/MathMLElement.webidl
index c54896c4e7..e370eda2b0 100644
--- a/dom/webidl/MathMLElement.webidl
+++ b/dom/webidl/MathMLElement.webidl
@@ -13,7 +13,7 @@
 [Exposed=Window]
 interface MathMLElement : Element { };
 MathMLElement includes GlobalEventHandlers;
-//MathMLElement includes HTMLOrForeignElement;
+MathMLElement includes HTMLOrForeignElement;
 MathMLElement includes DocumentAndElementEventHandlers;
 MathMLElement includes ElementCSSInlineStyle;
 MathMLElement includes TouchEventHandlers;
\ No newline at end of file
diff --git a/dom/webidl/SVGElement.webidl b/dom/webidl/SVGElement.webidl
index 866df8095f..592685a27b 100644
--- a/dom/webidl/SVGElement.webidl
+++ b/dom/webidl/SVGElement.webidl
@@ -15,18 +15,13 @@ interface SVGElement : Element {
 
   [Constant]
   readonly attribute SVGAnimatedString className;
-  [SameObject] readonly attribute DOMStringMap dataset;
 
   readonly attribute SVGSVGElement? ownerSVGElement;
   readonly attribute SVGElement? viewportElement;
-
-  [SetterThrows, Pure]
-        attribute long tabIndex;
-  [Throws] void focus();
-  [Throws] void blur();
 };
 
 SVGElement includes GlobalEventHandlers;
+SVGElement includes HTMLOrForeignElement;
 SVGElement includes DocumentAndElementEventHandlers;
 SVGElement includes ElementCSSInlineStyle;
 SVGElement includes TouchEventHandlers;
diff --git a/dom/webidl/XULElement.webidl b/dom/webidl/XULElement.webidl
index ab2300df53..9e43532c76 100644
--- a/dom/webidl/XULElement.webidl
+++ b/dom/webidl/XULElement.webidl
@@ -96,10 +96,6 @@ interface XULElement : Element {
   [Throws]
   readonly attribute BoxObject?                 boxObject;
 
-  [Throws]
-  void                      focus();
-  [Throws]
-  void                      blur();
   [Throws]
   void                      click();
   void                      doCommand();
@@ -134,6 +130,7 @@ interface mixin MozFrameLoaderOwner {
 
 XULElement includes GlobalEventHandlers;
 XULElement includes ElementCSSInlineStyle;
+XULElement includes HTMLOrForeignElement;
 XULElement includes TouchEventHandlers;
 XULElement includes MozFrameLoaderOwner;
 XULElement includes OnErrorEventHandlerForNodes;
diff --git a/dom/xul/nsXULElement.cpp b/dom/xul/nsXULElement.cpp
index b2f225cedf..12229d4e4a 100644
--- a/dom/xul/nsXULElement.cpp
+++ b/dom/xul/nsXULElement.cpp
@@ -1720,7 +1720,8 @@ NS_IMETHODIMP
 nsXULElement::Focus()
 {
     ErrorResult rv;
-    Focus(rv);
+    FocusOptions options;
+    Focus(options, rv);
     return rv.StealNSResult();
 }
 
diff --git a/layout/forms/nsNumberControlFrame.cpp b/layout/forms/nsNumberControlFrame.cpp
index a1dfd3c083..3f4cde6fd0 100644
--- a/layout/forms/nsNumberControlFrame.cpp
+++ b/layout/forms/nsNumberControlFrame.cpp
@@ -308,7 +308,11 @@ public:
   NS_IMETHOD Run() override
   {
     if (mNumber->AsElement()->State().HasState(NS_EVENT_STATE_FOCUS)) {
-      HTMLInputElement::FromContent(mTextField)->Focus();
+      // This job shouldn't be triggered by a WebIDL interface, hence the
+      // default options can be used.
+      FocusOptions options;
+      ErrorResult rv;
+      HTMLInputElement::FromContent(mTextField)->Focus(options, rv);
     }
 
     return NS_OK;
@@ -595,7 +599,11 @@ nsNumberControlFrame::HandleFocusEvent(WidgetEvent* aEvent)
   if (aEvent->mOriginalTarget != mTextField) {
     // Move focus to our text field
     RefPtr<HTMLInputElement> textField = HTMLInputElement::FromContent(mTextField);
-    textField->Focus();
+    // Use default FocusOptions, because this method isn't supposed to be called
+    // from a WebIDL interface.
+    FocusOptions options;
+    ErrorResult rv;
+    textField->Focus(options, rv);
   }
 }