title: Making an image scale on mouse over on a <canvas>
body: <p>I have a canvas, and I've drawn an image on it:</p>
  
  <pre><code>var imageObj = new Image();
  imageObj.onload = function() {
      context.drawImage(imageObj, 0, 0);
  };
  imageObj.src = 'http://localhost:8080/apache_pb2.png';
  </code></pre>
  
  <p>but I want to <code>scale</code> the image on mouse over. So I tried this code:</p>
  
  <pre><code>imageObj.onmouseover = function() {
      context.scale(2, 2);
  }
  </code></pre>
  
  <p>thinking I might get lucky -but no go -it doesn't even fire.</p>
  
  <p>However, to add insult to injury I can't seem to find a definitive reference on the HTML5 canvas so it's pretty difficult to determine what's available on the <code>Image</code> object.</p>
  
  <p>How can I attach to the <code>onmouseover</code> event? Is there even an <code>onmouseover</code> event?</p>