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);
 };
};