点击当前文字连接，使其背景色改变，其余连接不发生变化

/*----------------html代码-------------------------*/

<div class="left-menu">
<div id="line1"></div>

<div class="nav">
<ul >
        <li class="li-list"><a href="Teams.html" target="mainFrame">学期定义</a></li>
<li class="li-list"><a href="TeachPlans.html" target="mainFrame">教学计划管理</a></li>
<li class="li-list"><a href="TeachPlan.html" target="mainFrame">制定教学计划</a></li>
            <li class="li-list"><a href="CourseDispatch.html" target="mainFrame">派课信息管理</a></li>
</ul>
</div>
<div id="line1"></div>
<div class="nav">
<ul>
<li class="li-list"><a href="#">资料类别定义</a></li>
<li class="li-list"><a href="#">资料管理</a></li>
<li class="li-list"><a href="#">资料上传</a></li>
<li class="li-list"><a href="#">资料详情</a></li>
</ul>
</div>
<div id="line1"></div>
    <div class="nav">
<ul>
<li class="li-list"><a href="WkloadCriterion.html" target="mainFrame">三字经</a></li>
            <li class="li-list"><a href="TutorWkloadAssign.html" target="mainFrame">易经</a></li>
            <li class="li-list"><a href="ThesisGuidDispatch.html" target="mainFrame">阿什顿</a></li>
<li class="li-list"><a href="TutorWkloadAccnt.html" target="mainFrame">发表文章</a></li>
<li class="li-list"><a href="CoursewareWkloadAccnt.html" target="mainFrame">分类管理</a></li>
            <li class="li-list"><a href="#">评论管理</a></li>
<li class="li-list"><a href="#">做电子书</a></li>
            <li class="li-list"><a href="#">回收站</a></li>


</ul>
</div>
</div>

/*-----------------------css代码--------------------*/

.left-menu{ width:167px;}
.left-menu #line1{ width:125px; height:4px; background:url(../images/line1.png) no-repeat; margin-top:18px; margin-left:26px;}
.nav{margin-top:-5px; margin-left:-10px;}
.nav ul{ display:block; }
.nav ul li{ list-style:none; margin-bottom:5px;}
.nav a:link,.nav a:visited{ font-family:"黑体";font-size:14px; text-decoration:none; color:#000000;}
.nav a:hover{ text-decoration:underline;}

/*----------------------jquery代码-------------------------*/

$(document).ready(function(){

  $(".li-list").click(function(){
   $("li").siblings().css("background-color","");
   $(this).css("background-color","#D8D8D8");
   
  });
});