UserStoppedTyping.html

<script type="text/javascript">
/**----------------------------------------------------------------
  I reset timeOfLastKeyPress and the intervalId in the
  userStoppedTyping so that it can continue to run
-----------------------------------------------------------------*/
	var timeOfLastKeyPress = new Date().getTime() * 2; // make it in the future
	var maxMillisecondsBetweenKeystrokes = 600;
	var millisecondsBetweenCheckingForStoppage = 200;
	var intervalId = setInterval("userStoppedTyping()", millisecondsBetweenCheckingForStoppage);
	 
	var logKeyPress = function (){
	 timeOfLastKeyPress = new Date().getTime();
	 }
	 
	var userStoppedTyping = function(){
	  if(new Date().getTime() - timeOfLastKeyPress > maxMillisecondsBetweenKeystrokes){
		//this is where we do our expensive stuff.
                alert("You stopped typing - " + document.getElementById('field').value); 
		clearInterval(intervalId);
		timeOfLastKeyPress = new Date().getTime() * 2;
		intervalId = setInterval("userStoppedTyping()", millisecondsBetweenCheckingForStoppage);
	  }
	}
 
</script>
<input type="text" id="field" onkeypress="logKeyPress();">