determine if an object is a global object/constructor (based if it's non-enumerable properties of window)

is global item

// get all native objects key names (include non-enumerable properties)
var windowItems = Object.getOwnPropertyNames(window);

// exclude deprecated browser items to avoid console warnings
// the tradeoff is 'isOnWindow' will incorrect report false for these items
var deprecatedItems = ['webkitIDBTransaction',
	'webkitIDBRequest',
	'webkitIDBObjectStore',
	'webkitIDBKeyRange',
	'webkitIDBIndex',
	'webkitIDBFactory',
	'webkitIDBDatabase',
	'webkitIDBCursor',
	'webkitIndexedDB',
	'webkitStorageInfo'
]

for (var i = 0; i < deprecatedItems.length; i++) {
	var deprecatedIndex = windowItems.indexOf(deprecatedItems[i]);
	if (deprecatedIndex !== -1) {
		windowItems.splice(deprecatedIndex, 1);
	}
}

// get the values of all the keys
windowItems = windowItems.map(function getValue(key) {
	return window[key];
});

// determine if an item is on the global window object (Native constructors are)
function isOnWindow(item) {
	return windowItems.indexOf(item) !== -1;
}