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;
    }
}

方法二：

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;
}