diff --git a/baselines/dom.generated.d.ts b/baselines/dom.generated.d.ts
index 73fc0251f..ddee223b3 100644
--- a/baselines/dom.generated.d.ts
+++ b/baselines/dom.generated.d.ts
@@ -611,7 +611,7 @@ interface IntersectionObserverEntryInit {
 }
 
 interface IntersectionObserverInit {
-    root?: Element | null;
+    root?: Element | Document | null;
     rootMargin?: string;
     threshold?: number | number[];
 }
@@ -9611,7 +9611,7 @@ declare var InputEvent: {
 
 /** provides a way to asynchronously observe changes in the intersection of a target element with an ancestor element or with a top-level document's viewport. */
 interface IntersectionObserver {
-    readonly root: Element | null;
+    readonly root: Element | Document | null;
     readonly rootMargin: string;
     readonly thresholds: ReadonlyArray<number>;
     disconnect(): void;
diff --git a/inputfiles/idl/Intersection Observer.widl b/inputfiles/idl/Intersection Observer.widl
index 3b1e6018c..1b4f5d48a 100644
--- a/inputfiles/idl/Intersection Observer.widl	
+++ b/inputfiles/idl/Intersection Observer.widl	
@@ -1,19 +1,20 @@
-callback IntersectionObserverCallback = void (sequence<IntersectionObserverEntry> entries, IntersectionObserver observer);
+callback IntersectionObserverCallback = undefined (sequence<IntersectionObserverEntry> entries, IntersectionObserver observer);
 
-[Constructor(IntersectionObserverCallback callback, optional IntersectionObserverInit options),
- Exposed=Window]
+[Exposed=Window]
 interface IntersectionObserver {
-  readonly attribute Element? root;
+  constructor(IntersectionObserverCallback callback, optional IntersectionObserverInit options = {});
+  readonly attribute (Element or Document)? root;
   readonly attribute DOMString rootMargin;
   readonly attribute FrozenArray<double> thresholds;
-  void observe(Element target);
-  void unobserve(Element target);
-  void disconnect();
+  undefined observe(Element target);
+  undefined unobserve(Element target);
+  undefined disconnect();
   sequence<IntersectionObserverEntry> takeRecords();
 };
 
-[Constructor(IntersectionObserverEntryInit intersectionObserverEntryInit)]
+[Exposed=Window]
 interface IntersectionObserverEntry {
+  constructor(IntersectionObserverEntryInit intersectionObserverEntryInit);
   readonly attribute DOMHighResTimeStamp time;
   readonly attribute DOMRectReadOnly? rootBounds;
   readonly attribute DOMRectReadOnly boundingClientRect;
@@ -34,7 +35,7 @@ dictionary IntersectionObserverEntryInit {
 };
 
 dictionary IntersectionObserverInit {
-  Element?  root = null;
+  (Element or Document)?  root = null;
   DOMString rootMargin = "0px";
   (double or sequence<double>) threshold = 0;
 };
diff --git a/inputfiles/idlSources.json b/inputfiles/idlSources.json
index e3e3be65e..2aa4073b8 100644
--- a/inputfiles/idlSources.json
+++ b/inputfiles/idlSources.json
@@ -387,7 +387,7 @@
         "title": "Indexed Database"
     },
     {
-        "url": "https://www.w3.org/TR/intersection-observer/",
+        "url": "https://w3c.github.io/IntersectionObserver/",
         "title": "Intersection Observer"
     },
     {