[micscr]

<script src="http://code.jquery.com/jquery.min.js" type="text/javascript"></script>
 
<ul>
    <li>li0</li>
    <li>li1</li>
    <li class="now">now2</li>
</ul>
<hr>
<ul>
    <li>li0</li>
    <li>li1</li>
    <li>li2</li>
    <li class="now">now3</li>
</ul>
 
<script type="text/javascript">
$(function(){
  $('ul').click(function(){
         var $this = $(this);
	 var $lis = $this.find('li');
	 var $li1 = $this.find('li.now');
	 var ind = $lis.index($li1);
         alert(ind);
  });
});
</script>