title: Determine vertical direction of a touchmove
body: <p>i'm trying to implement a touch listener for tablets to trigger some actions depending whether it touchmoved upwards or downwards. </p>
  
  <p>I tried the native listener:</p>
  
  <pre><code>($document).bind('touchmove', function (e)
  {
      alert("it worked but i don't know the direction");
  });
  </code></pre>
  
  <p>But i don't know how to determine the direction. </p>
  
  <p>Is this possible? </p>
  
  <p>Or do i need to use touchstart/touchend, if I need this can I determine the direction before the touch movement stops?</p>
  
  <p>If I can only do this with an external library, what's the best one?</p>
  
  <p>thanks.</p>