title: What is the difference between window.onload() and document.addEventListener('load', ..)?
body: <p>It seems to me that both events are fired when every resource and its dependent resources have finished loading. This rises some questions:</p>
  
  <ol>
  <li>Is there any difference between those events?</li>
  <li>Which event gets fired first?</li>
  <li>Which event could or should be preferred for adding an additional HTML element to the body after everything has been finished loading?</li>
  </ol>