异步查找 DOM 节点.

by redky

HTML

<div></div>
  <div></div>
  <div></div>
  <div><div class="tag"></div></div>
  <div></div>
  <div></div>
  <div><div class="tag"></div></div>
  <div></div>
  <div></div>
  <div></div>

JavaScript

document.addEventListener('animationstart', function(e) {
  console.log('target:', e.target);
}, false);

function trigger() {
  var style = document.createElement('style');
  style.type = 'text/css';
  style.innerHTML = 'div.tag {\
    animation-duration:.001s;animation-name:demo;}\
    @keyframes demo{from{opacity:0.99;}to{opacity:1;}}';
  document.getElementsByTagName('head')[0].appendChild(style);
}
trigger();
console.log('end!');