n () {
      $('.mouseoverregion').text('');
    });
  }

  /**
   ** Draw the little mouse speed animated graph
   ** This just attaches a handler to the mousemove event to see
   ** (roughly) how far the mouse has moved
   ** and then updates the display a couple of times a second via
   ** setTimeout()
   **/
  function drawMouseSpeedDemo() {
    var mrefreshinterval = 500; // update display every 500ms
    var lastmousex = -1;
    var lastmousey = -1;
    var lastmousetime;
    var mousetravel = 0;
    