Selector: Use shallow equality to compare documents to avoid IE/Edge crashes

mgol · mgol · commit 686f2c7b8301 · 2019-08-27T01:20:30.000+02:00
IE/Edge sometimes crash when comparing documents between frames using the strict equality operator (`===` & `!==`). Funnily enough, shallow comparisons (`==` & `!=`) work without crashing. Fixes gh-4441
diff --git a/src/selector.js b/src/selector.js
@@ -173,7 +173,11 @@ function find( selector, context, results, seed ) {
 	// Try to shortcut find operations (as opposed to filters) in HTML documents
 	if ( !seed ) {
 
-		if ( ( context ? context.ownerDocument || context : preferredDoc ) !== document ) {
+		// Support: IE 11+, Edge 17 - 18+
+		// IE/Edge sometimes throw a "Permission denied" error when strict-comparing
+		// two documents; shallow comparisons work.
+		// eslint-disable-next-line eqeqeq
+		if ( ( context ? context.ownerDocument || context : preferredDoc ) != document ) {
 			setDocument( context );
 		}
 		context = context || document;
@@ -425,7 +429,11 @@ function setDocument( node ) {
 		doc = node ? node.ownerDocument || node : preferredDoc;
 
 	// Return early if doc is invalid or already selected
-	if ( doc === document || doc.nodeType !== 9 ) {
+	// Support: IE 11+, Edge 17 - 18+
+	// IE/Edge sometimes throw a "Permission denied" error when strict-comparing
+	// two documents; shallow comparisons work.
+	// eslint-disable-next-line eqeqeq
+	if ( doc == document || doc.nodeType !== 9 ) {
 		return;
 	}
 
