Javascript常见面试题-判断数组中是否有重复元素？

方法一:

代码如下: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:

代码如下: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:

代码如下:function isRepeat(arr){

var hash = {};

for(var i in arr) {

if(hash[arr[i]]) return true;

hash[arr[i]] = true;

return false;