Event for when file has loaded
===

The code below runs on a page:

    (function() {
      function asyncLoad() {
        var urls = ["https://something.com/script.js"];
        for (var i = 0; i < urls.length; i++) {
          var s = document.createElement('script');
          s.type = 'text/javascript';
          s.async = true;
          s.src = urls[i];
          var x = document.getElementsByTagName('script')[0];
          x.parentNode.insertBefore(s, x);
        }
      }
      window.attachEvent ? window.attachEvent('onload', asyncLoad) : window.addEventListener('load', asyncLoad, false);
    })();
    //]]>

I need an event listener that fires when this file is available in the DOM.

I need to utilize variables from this script. 

I need to know when `https://something.com/script.js` has been loaded and if it is not I would like a backup to fire. This can happen if the file hasn't loaded within a designated period of time.

Alternatively I could use an event for when a variable is available from the script.js file.