Javascript判断一个数组中是否有重复值的三种方法：判断重复方法一，转为字符串 进行比较:
var ary = new Array("aaa","cc","dd","aaa");
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;}
}
判断重复方法二，数组排序，再比较相邻的值:
var ary = new Array("bbb","cc","dd","bbb");
var nary=ary.sort();
for(var i=0;i<ary.length;i++){if (nary[i]==nary[i+1]){alert("数组重复内容为:"+nary[i]);}
}
判断重复方法三，自定义函数方法判断重复:
function isRepeat(arr){var hash = {};for(var i in arr) {if(hash[arr[i]])return true;hash[arr[i]] = true;}return false;
}