數組-去掉重複內容

Array.prototype.unip = function () {
        var temp = {},
            len = this.length;
        for (var i = 0; i < len; i++) {
            if (typeof temp[this[i]] == "undefined") {
                temp[this[i]] = 1;
            }
        }
        this.length = 0;
        len = 0;
        for (var i in temp) {
            this[len++] = i;
        }
        return this;
    }
    
    var arr = [1,2,3,4,4,4,4,4,4,5,5,6,6,7,7,5];
    
    arr.unip();
    alert(arr);