title: React.js, Is `DOMContentLoaded` equal with `componentDidMount`?
body: <p>People always say that you can get the <code>dom</code> in <code>componentDidMount</code>.</p>
  
  <p>Is that mean <code>componentDidMount</code> and <code>DOMContentLoaded</code> are synchronous, or does it mean when <code>componentDidMount</code>, the <code>dom</code> is always ready?</p>