JS判断一个数组中是否有重复值的三种方法

方法一：

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;
}
}

var ary = new Array("111","22","33","111");
var nary=ary.sort();
for(var i=0;i<ary.length;i++){
for(var k=i-1;k<ary.length;k++){
if (ary[i]==ary[k]){
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;
}