Refine the jQuery.isWindow check.

src/core.js

@@ -476,9 +476,8 @@ jQuery.extend({
 		return jQuery.type(obj) === "array";
 	},
 
-	// A crude way of determining if an object is a window
 	isWindow: function( obj ) {
-		return obj && typeof obj === "object" && "setInterval" in obj;
+		return obj != null && obj == obj.window;
 	},
 
 	isNumeric: function( obj ) {

test/unit/core.js

@@ -558,9 +558,10 @@ test("isXMLDoc - XML", function() {
 }
 
 test("isWindow", function() {
-	expect( 12 );
+	expect( 14 );
 
 	ok( jQuery.isWindow(window), "window" );
+	ok( jQuery.isWindow(document.getElementsByTagName("iframe")[0].contentWindow), "iframe.contentWindow" );
 	ok( !jQuery.isWindow(), "empty" );
 	ok( !jQuery.isWindow(null), "null" );
 	ok( !jQuery.isWindow(undefined), "undefined" );
@@ -570,8 +571,7 @@ test("isWindow", function() {
 	ok( !jQuery.isWindow(1), "number" );
 	ok( !jQuery.isWindow(true), "boolean" );
 	ok( !jQuery.isWindow({}), "object" );
-	// HMMM
-	// ok( !jQuery.isWindow({ setInterval: function(){} }), "fake window" );
+	ok( !jQuery.isWindow({ setInterval: function(){} }), "fake window" );
 	ok( !jQuery.isWindow(/window/), "regexp" );
 	ok( !jQuery.isWindow(function(){}), "function" );
 });