diff --git a/src/core.js b/src/core.js
index 890e9a2d..23b96442 100644
--- a/src/core.js
+++ b/src/core.js
@@ -316,7 +316,7 @@ jQuery.extend({
 	isXMLDoc: function( elem ) {
 		// 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";
+		return ((elem ? elem.ownerDocument || elem : 0).documentElement || 0).nodeName !== "HTML";
 	},
 
 	// Evalulates a script in a global context
diff --git a/test/unit/core.js b/test/unit/core.js
index b6dc2064..8decd494 100644
--- a/test/unit/core.js
+++ b/test/unit/core.js
@@ -280,10 +280,10 @@ test("isXMLDoc - HTML", function() {
 	document.body.appendChild( iframe );
 
 	try {
-		var body = jQuery(iframe).contents().find("body")[0];
-		ok( !jQuery.isXMLDoc( body ), "Iframe body element" );
+		var body = jQuery(iframe).contents()[0];
+		ok( jQuery.isXMLDoc( body ), "Iframe body element" );
 	} catch(e){
-		ok( false, "Iframe body element" );
+		ok( false, "Iframe body element exception" );
 	}
 
 	document.body.removeChild( iframe );