css3实现鼠标跟随导航效果

效果知识点：html/css布局思维, p+css讲解，css3动画，盒子模型, 浮动与定位，鼠标事件。

html代码：

<p class="wrap">
 <ul>
 <li style="background-position:0px 0px; border-top:1px dotted #ccc;border-left:1px dotted #ccc;"></li>
 <li style="background-position:-230px 0px; border-top:1px dotted #ccc"></li>
 <li style="background-position:-460px 0px; border-top:1px dotted #ccc"></li>
 <li style="background-position:-690px 0px; border-top:1px dotted #ccc"></li>
 <li style="background-position:-920px 0px; border-top:1px dotted #ccc"></li>
 <li style="background-position:-1150px 0px;border-left:1px dotted #ccc;"></li>
 <li style="background-position:-1370px 0px"></li>
 <li style="background-position:-1600px 0px"></li>
 <li style="background-position:-1830px 0px"></li>
 <li style="background-position:-2060px 0px"></li>
 <li style="background-position:-2290px 0px;border-left:1px dotted #ccc;"></li>
 <li style="background-position:-2520px 0px"></li>
 <li style="background-position:-2750px 0px"></li>
 <li style="background-position:-2980px 0px"></li>
 <li style="background-position:-3210px 0px"></li>
 </ul>
 <p class="box"></p>

css代码：

 <style>
 *{
 margin:0px;
 padding:0px;
 }
 html{
 height:100%;
 }
 body{
 width:100%;
 height:100%;
 background:url("images/wallpaper4.jpg");
 background-size:100% 100%;
 overflow: hidden;
 }
 .wrap{
 position:relative;
 width:1156px;
 height:450px;
 margin:50px auto;
 }
 .wrap ul li{
 position:relative;
 z-index:10;
 width:230px;
 height:150px;
 float:left;
 list-style:none;
 border-right:1px dotted #ccc;
 border-bottom:1px dotted #ccc;
 background:url("images/clients.png") no-repeat;
 -webkit-transition:1s;
 -moz-transition:1s;
 -ms-transition:1s;
 -o-transition:1s;
 transition:1s;
 }
 .box{
 position:absolute;
 left:0px;
 top:0px;
 z-index:2;
 width:230px;
 height:150px;
 background:rgba(0,0,0,.2);
 -webkit-transition:1s;
 -moz-transition:1s;
 -ms-transition:1s;
 -o-transition:1s;
 transition:1s;
 }
 </style>

javascript代码：