数组去重2

var arr = [1, 5, 6, 3, 8, 9, 2, 3, 1, 4, 5, , 8, 9, 5, 6, 4, 8, 9, 1, 2, 3, 4, 5, 8];

var arr1 = [];

for(var i = 0; i<arr.length; i++){

   if(arr1.indexOf(arr[i])==-1){

     arr1.

}

}