diff --git a/dom/events/EventNameList.h b/dom/events/EventNameList.h
index 391bf6e975113..593b6917b0358 100644
--- a/dom/events/EventNameList.h
+++ b/dom/events/EventNameList.h
@@ -167,6 +167,8 @@ EVENT(click, ePointerClick, EventNameType_All,
           ? ePointerEventClass
           : eMouseEventClass)
 EVENT(close, eClose, EventNameType_HTMLXUL, eBasicEventClass)
+EVENT(contentvisibilityautostatechange, eContentVisibilityAutoStateChange,
+      EventNameType_All, eBasicEventClass)
 EVENT(contextmenu, eContextMenu,
       EventNameType_HTMLXUL | EventNameType_SVGGraphic,
       StaticPrefs::dom_w3c_pointer_events_dispatch_click_as_pointer_event()
diff --git a/dom/webidl/EventHandler.webidl b/dom/webidl/EventHandler.webidl
index c88e4f0422cea..fb949f5cf2e41 100644
--- a/dom/webidl/EventHandler.webidl
+++ b/dom/webidl/EventHandler.webidl
@@ -39,6 +39,7 @@ interface mixin GlobalEventHandlers {
            attribute EventHandler onchange;
            attribute EventHandler onclick;
            attribute EventHandler onclose;
+           attribute EventHandler oncontentvisibilityautostatechange;
            attribute EventHandler oncontextlost;
            attribute EventHandler oncontextmenu;
            attribute EventHandler oncontextrestored;
diff --git a/testing/web-platform/meta/css/css-contain/content-visibility/content-visibility-auto-state-changed.html.ini b/testing/web-platform/meta/css/css-contain/content-visibility/content-visibility-auto-state-changed.html.ini
deleted file mode 100644
index 3ae60affb1143..0000000000000
--- a/testing/web-platform/meta/css/css-contain/content-visibility/content-visibility-auto-state-changed.html.ini
+++ /dev/null
@@ -1,16 +0,0 @@
-[content-visibility-auto-state-changed.html]
-  expected: TIMEOUT
-  [ContentVisibilityAutoStateChange fires when relevant element gains `content-visibility:auto` (oncontentvisibilityautostatechange syntax)]
-    expected: TIMEOUT
-
-  [ContentVisibilityAutoStateChange fires when not relevant element gains `content-visibility:auto`]
-    expected: NOTRUN
-
-  [ContentVisibilityAutoStateChange content attribute test]
-    expected: NOTRUN
-
-  [ContentVisibilityAutoStateChange fires when skipped]
-    expected: NOTRUN
-
-  [ContentVisibilityAutoStateChange fires when not skipped]
-    expected: NOTRUN
diff --git a/testing/web-platform/tests/css/css-contain/content-visibility/content-visibility-auto-state-changed.html b/testing/web-platform/tests/css/css-contain/content-visibility/content-visibility-auto-state-changed.html
index 0333c052e4a2e..6a14470c0f4b1 100644
--- a/testing/web-platform/tests/css/css-contain/content-visibility/content-visibility-auto-state-changed.html
+++ b/testing/web-platform/tests/css/css-contain/content-visibility/content-visibility-auto-state-changed.html
@@ -24,16 +24,22 @@
 
 <script>
 let contentattrfired = false;
+let contentattrfiredonsvg = false;
 
 function contentattrDidFire() {
   contentattrfired = true;
 }
 
+function contentattrDidFireOnSvg() {
+  contentattrfiredonsvg = true;
+}
+
 </script>
 
 <div id=upper></div>
 <div id=attrtest></div>
 <div id=contentattrtest oncontentvisibilityautostatechange="contentattrDidFire()" class=auto></div>
+<svg id="svgcontentattrtest" oncontentvisibilityautostatechange="contentattrDidFireOnSvg()" class="auto"></svg>
 <div class=spacer></div>
 <div id=middle></div>
 <div class=spacer></div>
@@ -83,6 +89,12 @@
   assert_true(contentattrfired, "contentattrfired");
 }, "ContentVisibilityAutoStateChange content attribute test");
 
+
+promise_test(async t => {
+  await waitForAtLeastOneFrame();
+  assert_true(contentattrfiredonsvg, "contentattrfiredonsvg");
+}, "ContentVisibilityAutoStateChange content attribute test on svg");
+
 promise_test(t => new Promise(async (resolve, reject) => {
   await new Promise((waited, _) => {
     requestAnimationFrame(() => requestAnimationFrame(waited));
diff --git a/widget/EventMessageList.h b/widget/EventMessageList.h
index 857c412bc8b38..94677ecc3919e 100644
--- a/widget/EventMessageList.h
+++ b/widget/EventMessageList.h
@@ -214,6 +214,9 @@ NS_EVENT_MESSAGE(ePageHide)
 NS_EVENT_MESSAGE(eContextLost)
 NS_EVENT_MESSAGE(eContextRestored)
 
+// content-visibility events
+NS_EVENT_MESSAGE(eContentVisibilityAutoStateChange)
+
 // SVG events
 NS_EVENT_MESSAGE(eSVGLoad)
 NS_EVENT_MESSAGE(eSVGScroll)
diff --git a/xpcom/ds/StaticAtoms.py b/xpcom/ds/StaticAtoms.py
index 82c9e3ca64bfa..51c68a4d1a368 100644
--- a/xpcom/ds/StaticAtoms.py
+++ b/xpcom/ds/StaticAtoms.py
@@ -787,6 +787,7 @@
     Atom("onCheckKeyPressEventModel", "onCheckKeyPressEventModel"),
     Atom("onclick", "onclick"),
     Atom("onclose", "onclose"),
+    Atom("oncontentvisibilityautostatechange", "oncontentvisibilityautostatechange"),
     Atom("oncommand", "oncommand"),
     Atom("oncommandupdate", "oncommandupdate"),
     Atom("oncomplete", "oncomplete"),