SOURCE

var removeElement1 = function(nums, val) {
  while (nums.indexOf(val) > -1) { // 判断nums中是否存在val(利用indexOf寻找val是否存在或存在的位置) 存在就删除val
    nums.splice(nums.indexOf(val), 1);
  }
  return nums.length;
};

var removeElement2 = function(nums, val) {
    var index = 0;
    for (var i = 0; i < nums.length; i++) {
        if (nums[i] != val) {
            nums[index] = nums[i];
            index++;
        }
    }
    nums = nums.slice(0,index);
    return index;
};
var nums1 = [0,1,2,2,3,0,4,2], val1 = 2;
var nums2 = [0,1,2,2,3,0,4,2], val2 = 2;
console.log(removeElement1(nums1, val1));
console.log(removeElement2(nums2, val2));