li 标签中放a 标签，文字垂直居中

 <ul style="float:left"><li  class="lili">
                <a href="Left.aspx?type=214" rel="external nofollow"  target="leftFrame" class="imageA"><span style="Letter-spacing :1px;  position:relative; color:#900;">对标系统</span></a>
               </li>
               <li  class="lili">
                <a href="Left.aspx?type=225" rel="external nofollow"  target="leftFrame" class="imageA"><span style="Letter-spacing :1px; position:relative; color:#900;">绩效考核</span></a>
               </li>
               <li  class="lili">
                <a href="Left.aspx?type=235" rel="external nofollow"  target="leftFrame" class="imageA"><span style="Letter-spacing :1px; position:relative; color:#900;">内部数据</span></a>
               </li>
               <li  class="lili">
                <a href="Left.aspx?type=239" rel="external nofollow"  target="leftFrame" class="imageA"><span style="Letter-spacing :1px; position:relative; color:#900;">外部数据</span></a>
               </li>
               <li  class="lili">
                <a href="Left.aspx?type=59" rel="external nofollow"  target="leftFrame" class="imageA"><span style="Letter-spacing :1px; position:relative; color:#900;">系统管理</span></a>
               </li>
               </ul>

　　上面这段代码中，想让a标签中的文字居中，需要设置li标签的line-height 和height属性；

<style type="text/css">
.imageA
{
background-image:url(../App_Themes/DefaultTheme/images/top_nav.jpg);
background-repeat:no-repeat;
display:block;
width:110px;
height:29px;
 text-align:center;
 font-size:14px;
  color:#900;
 font-weight:bold; }
.lili
{
display:block;
width:110px;
height:29px;
line-height:31px;
float:left
}
</style>

　　有时候li 标签 水平显示（style=“float：left”），它的外面一层 的高度可能比它高一些。为了让它里面的a标签的文字居中，就需要把它的行高设置成和它外层的行高一样高就可以了！