Array.prototype.unique = function () {    var res = [], hash = {};    for (var i = 0, elem; (elem = this[i]) != null; i++) {        if (!hash[elem]) {            res.push(elem);            hash[elem] = true;        }    }    return res;}

 

使用

var arr = new Array(1, 3, 4, 5, 3);arr = arr.unique();alert(arr.join(","))  //输出1,3,4,5