Javascript Function to wait for specific time after user Types

 <script type="text/javascript">
        var typewatch = function () {
            var timer = 0;
            return function (callback, ms) {
                clearTimeout(timer);
                timer = setTimeout(callback, ms);
                if (timer != 0) {
                    callserver();
                }
            }
        } ();
    </script>

 <input type="text" onKeyUp="typewatch(function(){alert('Time elapsed!')}, 2000 );" />