// check if an element is in a (or is an) XML document
isXMLDoc: function( elem ) {
- return (elem.ownerDocument || elem).documentElement.nodeName !== "HTML";
+ // documentElement is verified for cases where it doesn't yet exist
+ // (such as loading iframes in IE - #4833)
+ return ((elem.ownerDocument || elem).documentElement || 0).nodeName !== "HTML";
},
// Evalulates a script in a global context