object.keys.js

if (!Object.keys) {
	Object.keys = (function () {
		var hasOwnProperty = Object.prototype.hasOwnProperty,
		hasDontEnumBug = !({
			toString : null
		}).propertyIsEnumerable('toString'),
		dontEnums = [
			'toString',
			'toLocaleString',
			'valueOf',
			'hasOwnProperty',
			'isPrototypeOf',
			'propertyIsEnumerable',
			'constructor'
		],
		dontEnumsLength = dontEnums.length
			
			return function (obj) {
			if (typeof obj !== 'object' && typeof obj !== 'function' || obj === null)
				throw new TypeError('Object.keys called on non-object')
				
				var result = []
				
				for (var prop in obj) {
					if (hasOwnProperty.call(obj, prop))
						result.push(prop)
				}
			
			if (hasDontEnumBug) {
				for (var i = 0; i < dontEnumsLength; i++) {
					if (hasOwnProperty.call(obj, dontEnums[i]))
						result.push(dontEnums[i])
				}
			}
			return result
		}
	})()
};