javascript數組去除重複數據

Array.prototype.uniq = 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; 
    }