title: javascript equivalent of 'mouseleave' for touch interactions
body: <p>Prelim caveat: I am very new to js and have mainly gotten by through doing web searches for examples/tutorials.</p>
  
  <p>I am writing js which should run both on web and on mobile devices (e.g. iPad).</p>
  
  <p>We have a library to help abstract away the differences between <code>mouse</code> and <code>touch</code>:</p>
  
  <pre><code>if (navigator.userAgent.search('Mobile') &gt; 0) {
    window.FLAGS = {
      start: 'touchstart',
      end: 'touchend',
      move: 'touchmove',
      click: 'click',
      touchScreen: true
    };
  } else {
    window.FLAGS = {
      start: 'mousedown',
      end: 'mouseup',
      move: 'mousemove',
      click: 'click',
      touchScreen: false
    };
  }
  </code></pre>
  
  <p>Then in code you can do things like:</p>
  
  <pre><code>widget.view.bind(FLAGS.start, function(e) {
  </code></pre>
  
  <p>I am trying to find a <code>touch</code> equivalent for <code>mouseleave</code> so I can do a similar trick.</p>
  
  <p>I can imagine ways to catch a <code>leave</code> event by tracking the position on <code>move</code> and comparing that to bounding box of widget in question, but I'm hoping there's a little one-liner like the <code>touchstart</code>/<code>mousedown</code> relationship.</p>