数组去重的几种方法，从数组中选择出互不重复的5个数

var arr = [1,1,2,2,2,3,3,3,4,5,6,8];var newarr = [];    newarr[0] = arr[0]         for(var i=0; i<arr.length; i++){      if(newarr.indexOf(arr[i]) == -1){         newarr.push(arr[i]);         if(newarr.length > 4){                  break;        }      }   }