title: Google Extension not finding existing elements
body: <p>I am building a chrome extension that is made to automate some of the more boring tasks of a website. The website seems to  be running a  Java Webapp rather than using typical JavaScript (I think this because the url never changes. it stays  as  <code>longurl/player/</code> but I am not familiar whatsoever  so there  is  a good chance I am  completely wrong with  this guess.)</p>
  
  <p>The issue I am having is when  I'm calling a <code>document.getElementsByClass</code> or <code>document.getElementById</code> after making some progress within the website (in this case moving to the next slide)  google seems to lose track of the elements of the page. This is not an issue with my script as the google debug console also cannot find these elements.  (Shown Below)</p>
  
  <p><a href="https://i.stack.imgur.com/KRBbk.png" rel="nofollow noreferrer">Console View</a>
  <a href="https://i.stack.imgur.com/FiDmj.png" rel="nofollow noreferrer">Page Source</a></p>
  
  <p>The most strange   thing   about   this  to  me  is that when I go up and  edit the page source as HTML 
   (not even changing   anything just hitting  the button  and clicking out) the console is then able to find the element just fine. Is this a common issue? Or is it just something simple that I  am overlooking? </p>