code: function(another) {
                  if (!another instanceof Box) {
                      another = new Box(another);
                  }
                  var left = Math.max(this.left, another.left), right = Math.min(this.right, another.right), top = Math.max(this.top, another.top), bottom = Math.min(this.bottom, another.bottom);
                  if (left > right || top > bottom) return new Box();
                  return new Box(left, top, right - left, bottom - top);
              }
docs: @method intersect()
  @for kity.Box
  @description 求当前矩形区域和指定的矩形区域重叠的矩形区域
  
  @grammar intersect(another) => {kity.Box}
  @param  {kity.Box} another 要求重叠的矩形区域
  
  @example
  
  ```js
  var box1 = new kity.Box(10, 10, 50, 50);
  var box2 = new kity.Box(30, 30, 50, 50);
  var box3 = box1.intersect(box2);
  console.log(box3.valueOf()); // [30, 30, 20, 20]
  ```