Open external links in new window with jQuery

gistfile1.html

<!-- open external links in new window -->
<script type="text/javascript">
jQuery(document).ready(function($) {
	$('div.entry-content a, aside.sidebar a').each(function() {
	   var a = new RegExp('/' + window.location.host + '/');
	   if(!a.test(this.href)) {
	       $(this).click(function(event) {
	           event.preventDefault();
	           event.stopPropagation();
	           window.open(this.href, '_blank');
	       });
	   }
	}).addClass('externallink');	
});
</script>