js去掉数组重复的扩展方法

Array.prototype.distinct　= function () {
	var thix = this,
		_a = this.concat().sort(),
		n = 0;
	_a.sort(function (a, b) {
		if(a === b) {
			n = thix.indexOf(a);
			thix.splice(n,1);
		}
	});
	return thix;
};
var arr = new Array(1,20,3,4,5,6,70,8,1,2,8);
arr.distinct();