<script language="javascript" type="text/javascript">
// 生成两级目录索引列表
function GenerateContentList()
{
 var mainContent = $('#cnblogs_post_body');
 var h2_list = $('#cnblogs_post_body h2');　　//如果你的章节标题不是h2,只需要将这里的h2换掉即可

 if(mainContent.length < 1)
  return;
 
 if(h2_list.length>0)
 {
  var content = '<a name="_labelTop"></a>';
  content += '<div id="navCategory">';
  content += '<p style="font-size:18px"><b>目录</b></p>';
  content += '<ul>';
  for(var i=0; i<h2_list.length; i++)
  {
   var go_to_top = '<div style="text-align: right"><a href="#_labelTop">回到顶部</a><a name="_label' + i + '"></a></div>';
   $(h2_list[i]).before(go_to_top);
   
   var h3_list = $(h2_list[i]).nextAll("h3");
   var li3_content = '';
   for(var j=0; j<h3_list.length; j++)
   {
    var tmp = $(h3_list[j]).prevAll('h2').first();
    if(!tmp.is(h2_list[i]))
     break;
    var li3_anchor = '<a name="_label' + i + '_' + j + '"></a>';
    $(h3_list[j]).before(li3_anchor);
    li3_content += '<li><a href="#_label' + i + '_' + j + '">' + $(h3_list[j]).text() + '</a></li>';
   }
   
   var li2_content = '';
   if(li3_content.length > 0)
    li2_content = '<li><a href="#_label' + i + '">' + $(h2_list[i]).text() + '</a><ul>' + li3_content + '</ul></li>';
   else
    li2_content = '<li><a href="#_label' + i + '">' + $(h2_list[i]).text() + '</a></li>';
   content += li2_content;
  }
if($('#cnblogs_post_body').length != 0 )
  {
   $($('#cnblogs_post_body')[0]).prepend(content);
  }
 } 
}

GenerateContentList();
</script>

#cnblogs_post_body h2 {
 background-repeat: no-repeat;
 background-image:url('http://xxxx');
}