down" class="underline">clicked</a></li>
  <li>a <a href="http://www.w3schools.com/jsref/met_document_addeventlistener.asp" class="underline">document event listener</a> to trigger the setPosition() (user’s mouse current position) function when mouse is moved over the <a href="https://developer.mozilla.org/en-US/docs/Web/Events/mouseenter" class="underline">canvas function</a></li>
</ul>

<div class="language-js highlighter-rouge"><div class="highlight"><pre class="highlight"><code>
<span class="c1">// ad