按钮3D效果

<style type="text/css">
<!--
.over {BORDER-LEFT: medium none; BORDER-RIGHT: medium none;
    BORDER-TOP: medium none; BORDER-BOTTOM: 1px solid #000000
    }
.down {BORDER-LEFT: medium none; BORDER-RIGHT: medium none;
    BORDER-TOP: medium none; BORDER-BOTTOM: medium none;COLOR:black
    }
-->
</style>

 

<input type="button" class="down" onMouseOver="this.className='over';"
  onMouseOut="this.className='down';"  value="按一下试试"
 name="Button">