title: Conditionally load JavaScript file
body: <p>I need a JS statement that determine which JavaScript file to use.</p>
  
  <p>I have one file:</p>
  
  <pre><code>&lt;script type="text/javascript" src="js/jquery_computer.js"&gt;&lt;/script&gt;
  </code></pre>
  
  <p>But when the screen width is less than 500px, I want load another file instead:</p>
  
  <pre><code>&lt;script type="text/javascript" src="js/mobile_version.js"&gt;&lt;/script&gt;
  </code></pre>
  
  <p>I have tried everything and it is not working.</p>