Clean up expando removal code - only try to delete the expando from an element if it's possible.

src/data.js

@@ -79,15 +79,8 @@ jQuery.extend({
 
 		// Otherwise, we want to remove all of the element's data
 		} else {
-			// Clean up the element expando
+			if ( jQuery.support.deleteExpando ) {
-			try {
 				delete elem[ expando ];
-			} catch( e ) {
-				// IE has trouble directly removing the expando
-				// but it's ok with using removeAttribute
-				if ( elem.removeAttribute ) {
-					elem.removeAttribute( expando );
-				}
 			}
 
 			// Completely remove the data cache
@@ -132,22 +125,3 @@ jQuery.fn.extend({
 		});
 	}
 });
-
-var removeExpando = function( elem ) {
-	delete elem[ expando ];
-};
-
-try {
-	var div = document.createElement("div");
-	div[ expando ] = true;
-	delete div[ expando ];
-	
-} catch( e ) {
-	// IE has trouble directly removing the expando
-	// but it's ok with using removeAttribute
-	removeExpando = function( elem ) {
-		if ( elem.removeAttribute ) {
-			elem.removeAttribute( expando );
-		}
-	};
-}

src/manipulation.js

@@ -547,7 +547,9 @@ jQuery.extend({
 	},
 	
 	cleanData: function( elems ) {
-		var data, id, cache = jQuery.cache, special = jQuery.event.special;
+		var data, id, cache = jQuery.cache,
+			special = jQuery.event.special,
+			deleteExpando = jQuery.support.deleteExpando;
 		
 		for ( var i = 0, elem; (elem = elems[i]) != null; i++ ) {
 			id = elem[ jQuery.expando ];
@@ -566,7 +568,9 @@ jQuery.extend({
 					}
 				}
 				
-				removeExpando( elem );
+				if ( deleteExpando ) {
+					delete elem[ expando ];
+				}
 				
 				delete cache[ id ];
 			}

src/support.js

@@ -59,6 +59,7 @@
 		parentNode: div.removeChild( div.appendChild( document.createElement("div") ) ).parentNode === null,
 
 		// Will be defined later
+		deleteExpando: true,
 		checkClone: false,
 		scriptEval: false,
 		noCloneEvent: true,
@@ -110,6 +111,17 @@
 		document.body.appendChild( div );
 		jQuery.boxModel = jQuery.support.boxModel = div.offsetWidth === 2;
 		document.body.removeChild( div ).style.display = 'none';
+
+		// Test to see if it's possible to delete an expando from an element
+		// Fails in Internet Explorer
+		try {
+			div.test = 1;
+			delete doc.test;
+	
+		} catch(e) {
+			jQuery.support.deleteExpando = false;
+		}
+
 		div = null;
 	});