if (!Array.prototype.filter) {
	Array.prototype.filter = function (func, thisArg) {
		'use strict';
		if (!((typeof func === 'Function' || typeof func === 'function') && this))
			throw new TypeError();

		var len = this.length >>> 0,
			res = new Array(len), // preallocate array
			t = this, c = 0, i = -1;
		if (thisArg === undefined) {
			while (++i !== len) {
				// checks to see if the key was set
				if (i in this) {
					if (func(t[i], i, t)) {
						res[c++] = t[i];
					}
				}
			}
		}
		else {
			while (++i !== len) {
				// checks to see if the key was set
				if (i in this) {
					if (func.call(thisArg, t[i], i, t)) {
						res[c++] = t[i];
					}
				}
			}
		}

		res.length = c; // shrink down array to proper size
		return res;
	};
}