title: Fetch an html element from external page with javascript
body: <p>I'm trying to create a function in javascript the will create a video html element, and get the source by retrieving a source element from another web page</p>
  
  <p>I've seen other questions with answers using jquery or some ajax stuff, but nobody actually explains themselves, so all I can do is copy and paste whatever they say into my page and get an error saying "$" is undefined (I'm rather new to javascript if you couldn't tell. Haven't used any ajax or jquery yet).</p>
  
  <pre><code>function loadSource(url){
      var vid = document.getElementById("vid");
      var src = &lt;get source element with id "mp4Source" from the specified url&gt;
      vid.appendChild(src);
  }
  </code></pre>