title: check to see if then load external scripts if they arent present
body: <p>I have 3 external files that have to be loaded for my adverts to display</p>
  
  <pre><code> http://www.manx.net/Scripts/jquery-1.6.1.min.js?v=12.01.2012
   http://www.manx.net/Scripts/jquery-migrate-1.2.1.min.js?v=12.01.2012
   https://code.createjs.com/createjs-2015.11.26.min.js
  </code></pre>
  
  <p>Problem is, if i have 2 of our adverts running at the same time on the adserver they conflict as they are both trying to pull the external files in at the same time. (i have to include these files in my advert each time as the adserver randomly picks the adverts to display).</p>
  
  <p>Is there a way that i can scan to see if the files are already loaded on the page, if they are do nothing and run the rest of the file. If they arent loaded then load and run the rest of the file that follows.</p>
  
  <p>Cheers</p>