Easiest/Lightest Replacement For Browser Detection jQuery 1.9?

I’ve use the following code answered by Alexx Roche, but i wanted to detect MSIE so:

<script type="text/javascript">
   $(document).ready(function() {
      if (navigator.userAgent.match(/msie/i) ){
        alert('I am an old fashioned Internet Explorer');
      }
   });
</script>

hope it helps!