js中如何实现数组去重--面试题

 1 function dupRemove(arr){
 2     var tmp = [];
 3     for(var i=0;i<arr.length;i++){
 4         for(var j=i+1;j<arr.length;j++){
 5             if(arr[i] === arr[j]){
 6                 j = ++i;
 7             }
 8         }
 9         tmp.push(arr[i]);
10     }
11     return tmp;
12 }
13 
14 var list = [10,20,50,60,10,20,'a','v','a'];
15 document.write(dupRemove(list)); //50,60,10,20,v,a