s="nx">y</span> <span class="o">=</span> <span class="nx">e</span><span class="p">.</span><span class="nx">clientY</span><span class="p">;</span>
  <span class="p">}</span>
</code></pre></div></div>

<p>At last, we come to our draw() function. Our function will need a <a href="https://developer.mozilla.org/en-US/docs/Web/JavaScript/Closures" class="underline">closure</a> followed by the following:</p>

<ul>
  <li>in the function, we need to have an <a href="http://www.w3schools.com/js/js_if_else.asp" class=