Array.prototype.forEach = function(callback, thisArg) {

	var T, k;

	if (this === null) {
		throw new TypeError(' this is null or not defined');
	}

	// 1. Let O be the result of calling toObject() passing the
	// |this| value as the argument.
	var O = Object(this);

	// 2. Let lenValue be the result of calling the Get() internal
	// method of O with the argument "length".
	// 3. Let len be toUint32(lenValue).
	var len = O.length >>> 0;

	// 4. If isCallable(callback) is false, throw a TypeError exception.
	// See: http://es5.github.com/#x9.11
	if (typeof callback !== "function") {
		throw new TypeError(callback + ' is not a function');
	}

	// 5. If thisArg was supplied, let T be thisArg; else let
	// T be undefined.
	if (arguments.length > 1) {
		T = thisArg;
	}

	// 6. Let k be 0
	k = 0;

	// 7. Repeat, while k < len
	while (k < len) {

		var kValue;

		// a. Let Pk be ToString(k).
		//    This is implicit for LHS operands of the in operator
		// b. Let kPresent be the result of calling the HasProperty
		//    internal method of O with argument Pk.
		//    This step can be combined with c
		// c. If kPresent is true, then
		if (k in O) {

			// i. Let kValue be the result of calling the Get internal
			// method of O with argument Pk.
			kValue = O[k];

			// ii. Call the Call internal method of callback with T as
			// the this value and argument list containing kValue, k, and O.
			callback.call(T, kValue, k, O);
		}
		// d. Increase k by 1.
		k++;
	}
	// 8. return undefined
};