js判断数组中是否有重复值得三种方法

方法一: 

function isRepeat() {    var ary = new Array("111", "22", "33", "111");    var s = ary.join(",") + ",";    for (var i = 0; i < ary.length; i++) {        if (s.replace(ary[i] + ",", "").indexOf(ary[i] + ",") > -1) {            alert("数组中有重复元素：" + ary[i]);            break;        }    }}

方法二: 

function isRepeat() {    var ary = new Array("111", "22", "33", "111");    var nary = ary.sort();    for (var i = 0; i < ary.length; i++) {        if (nary[i] == nary[i + 1]) {            alert("数组重复内容：" + nary[i]);        }    }}

方法三: 

function isRepeat(arr) {    var hash = {};    for (var i in arr) {        if (hash[arr[i]]){            return true;         }        hash[arr[i]] = true;    }    return false;}