title: Chrome can't read style.display value
body: <p>I have a weird problem.
  I try to write a GreaseMonkey script to be run in Firefox and Google Chrome.
  With Chrome I tried 2 extensions : "TamperMonkey" and "Blank Canvas Script Handler", mainly because my script check regulary for a new version on an external site and this is considered as cross site scripting and not authorized in Chrome.</p>
  
  <p>To show you my problem, I write a simple test case :</p>
  
  <pre><code>// ==UserScript==
  // @name        test
  // @namespace       http://fgs.ericc-dream.fr.nf
  // @description     test gm script
  // @include         http://gaia.fallengalaxy.eu/
  // @author          ericc
  // @version         0.0.1
  // ==/UserScript==
  
  /* We attach an event listener to the body tag and trigger the function
   * 'message' each time that an element is inserted in the page */
  var el = document.body;
  el.addEventListener('DOMNodeInserted', message, false);
  
  var extraFlag = false;
  
  function message(event) {
      /* first we capture the id of the new inserted element
       * (the one who created the event) */
      var objId = event.target.id;
  
      /* add an event listener on the map container */
      if (objId == "extra") {
          el = document.getElementById('extra');
          el.addEventListener('DOMSubtreeModified',readTest,false);
          GM_log(el.style.display);
      }
  }
  
  function readTest() {
      el = document.getElementById('extra');
      GM_log(extraFlag);
      GM_log(el.style.display);
      if ((el.style.display != 'none') &amp;&amp; (!extraFlag)) {
          alert('extra');
          extraFlag = true;
      } else if ((el.style.display == 'none')) {
          extraFlag = false;
      }
  }
  </code></pre>
  
  <p>the div element 'extra' is modified by the page. The problem is that Chrome is unable to read the value of el.style.display and thus extraFlag never become 'false' again.
  I use this flag to avoid to run the code several time, the site is heavily JavaScript driven
  This code work nicely in Firefox ! </p>
  
  <p>I tried to search with Google but can't find a correct answers. Seems easy to change the value of display, but it seems that I'm the only one who try to read it !!!</p>
  
  <p>I write this code because "DOMAttrModified" isn't supported in Chrome :-( </p>
  
  <p>Thanks in advance for your help </p>
  
  <p>ericc</p>