title: document.getElementById() returns null on IE9
body: <p>I'm working on a popup and i'm having some hard time with Internet Explorer 9. This is the piece of code that gives me trouble:</p>
  
  <pre><code>var popUp= document.getElementById('projectInfo');
  popUp.style.left=(tempX-310)+'px';
  popUp.style.top=(tempY-110)+'px';
  </code></pre>
  
  <p>In IE9 (haven't tested in prior versions), popup is null. In adition, i've tried including my .js file just before the body closing tag and wrapping my function in a "document.ready()" function but none of this worked. The same code though works perfectly in Opera, Chrome and Firefox. 
  Does anyone know what's going on?</p>
  
  <p>Note: The function is called in the body's onLoad atribute of my html.</p>