title: Browser support for readyState interactive?
body: <p>I'm building a web app that has to work on very old browsers (IE 8, Firefox 20, etc).</p>
  
  <p>Can I rely on <a href="https://developer.mozilla.org/en-US/docs/Web/API/Document/readyState" rel="nofollow">document.readyState being interactive and complete</a> working correctly?</p>
  
  <p>Basically, I want to perform some action after the DOM loads, but perform the action immediately if it has already loaded. Like this:</p>
  
  <pre><code>if (document.readyState == 'interactive' ||
      document.readyState == 'complete') {
    doAction();
  } else {
    document.onready = doAction;
  }
  </code></pre>