          if (y > window.innerHeight - this.el.tip.offsetHeight - 20) {
                  y -= this.el.tip.offsetHeight;
                } else {
                  y += 10;
                }

                if (this.el.tip) {
                  this.el.tip.style.top = y + 'px';
                  this.el.tip.style.left = x + 'px';
                }
              }
            } else {
              document.getElementById("tip").style.visibility = "hidden";
            }
          });

          this.el.sele