Javascript实现鼠标点击冒泡特效

onload = function() {
 var click_cnt = 0;
 var $html = document.getElementsByTagName("html")[0];
 var $body = document.getElementsByTagName("body")[0];
 $html.onclick = function(e) {
 var $elem = document.createElement("b");
 $elem.style.color = "#E94F06";
 $elem.style.zIndex = 9999;
 $elem.style.position = "absolute";
 $elem.style.select = "none";
 var x = e.pageX;
 var y = e.pageY;
 $elem.style.left = (x - 10) + "px";
 $elem.style.top = (y - 20) + "px";
 clearInterval(anim);
 switch (++click_cnt) {
  case 10:
  $elem.innerText = "OωO";
  break;
  case 20:
  $elem.innerText = "(๑•́ ∀ •̀๑)";
  break;
  case 30:
  $elem.innerText = "(๑•́ ₃ •̀๑)";
  break;
  case 40:
  $elem.innerText = "(๑•̀_•́๑)";
  break;
  case 50:
  $elem.innerText = "（￣へ￣）";
  break;
  case 60:
  $elem.innerText = "(╯°口°)╯(┴—┴";
  break;
  case 70:
  $elem.innerText = "૮( ᵒ̌皿ᵒ̌ )ა";
  break;
  case 80:
  $elem.innerText = "╮(｡>口<｡)╭";
  break;
  case 90:
  $elem.innerText = "( ง ᵒ̌皿ᵒ̌)ง⁼³₌₃";
  break;
  case 100:
  case 101:
  case 102:
  case 103:
  case 104:
  case 105:
  $elem.innerText = "(ꐦ°᷄д°᷅)";
  break;
  default:
  $elem.innerText = "❤";
  break;
 }
 $elem.style.fontSize = Math.random() * 10 + 8 + "px";
 var increase = 0;
 var anim;
 setTimeout(function() {
  anim = setInterval(function() {
  if (++increase == 150) {
   clearInterval(anim);
   $body.removeChild($elem);
  }
  $elem.style.top = y - 20 - increase + "px";
  $elem.style.opacity = (150 - increase) / 120;
  }, 8);
 }, 70);
 $body.appendChild($elem);
 };
};