利用for循环给数组去重
function del(arr,val){
var numDeleteIndex = -1;
for (var i = 0;i < arr.length; i++){
if (arr[i] === val){
arr.splice(i, 1);
numDeleteIndex = i;
break;
}
}
}
var arr = [1,2,3,3,4,5,5,6];
del(arr,3);
console.log(arr);
// [1, 2, 3, 4, 5, 5, 6]