鼠标移动,背景变色
<style>
.first {background:#666;}
.gray {background:red;}
</style>
<div class="first" onmouseover="this.className='gray'" onmouseout="this.className='first'">
.first {background:#666;}
.gray {background:red;}
</style>
<div class="first" onmouseover="this.className='gray'" onmouseout="this.className='first'">
