先来看张图片： 
原理就是通过背景的左对齐和右对齐用A标签和span标签组合出一个完整的圆角矩形。再通过hover标签去滑动图片。而你只需要一张图片：
ok，看看代码吧。
CSS:
复制代码 代码如下:
*{margin:0; padding:0;}
body{padding:10px; font-size:12px;}
h1{margin:0; padding:10px 0; font-size:14px; font-weight:bold;}
a{background:url(1.gif) left 0; color:#fff; text-decoration:none; height:30px; float:left; cursor:hand; margin:0 5px 0 0;}
a:hover{background:url(1.gif) left -30px;height:30px;}
a span{background:url(1.gif) right 0; padding:7px 8px 7px 0; margin:0 0 0 8px; float:left; height:16px;}
a:hover span{background:url(1.gif) right -30px; color:#000; padding:7px 8px 7px 0; margin:0 0 0 8px; height:16px; }
HTML:
复制代码 代码如下:
<body>
<h1><strong>CSS自适应宽度圆角按钮 @5key.net</strong></h1>
<a href=”#”><span>首页</span></a>
<a href=”#”><span>不是首页</span></a>
<a href=”#”><span>他也许是首页</span></a>
<a href=”#”><span>但他一定不是首页</span></a>
<a href=”#”><span>好了，就这样把。别扯了~</span></a>
</body>
演示：
<!DOCTYPE html PUBLIC “-//W3C//DTD XHTML 1.0 Transitional//EN” “http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd”> <html xmlns=”http://www.w3.org/1999/xhtml”> <head> <meta http-equiv=”Content-Type” content=”text/html; charset=gb2312″ /> <title>CSS自适应宽度按钮</title> <style> *{margin:0; padding:0;} body{padding:10px; font-size:12px;} h1{margin:0; padding:10px 0; font-size:14px; font-weight:bold;} a{background:url(/upload/20071122231110605.gif) left 0; color:#fff; text-decoration:none; height:30px; float:left; cursor:hand; margin:0 5px 0 0;} a:hover{background:url(/upload/20071122231110605.gif) left -30px;height:30px;} a span{background:url(/upload/20071122231110605.gif) right 0; padding:7px 8px 7px 0; margin:0 0 0 8px; float:left; height:16px;} a:hover span{background:url(/upload/20071122231110605.gif) right -30px; color:#000; padding:7px 8px 7px 0; margin:0 0 0 8px; height:16px; } </style> </head> <body> <h1><strong>CSS自适应宽度圆角按钮</strong></h1> <a href=”https://www.jb51.net” target=”_blank”><span>首页</span></a> <a href=”https://www.jb51.net” target=”_blank”><span>不是首页</span></a> <a href=”https://www.jb51.net” target=”_blank”><span>他也许是首页</span></a> <a href=”https://www.jb51.net” target=”_blank”><span>但他一定不是首页</span></a> <a href=”https://www.jb51.net” target=”_blank”><span>好了，就这样把。别扯了~</span></a> </body> </html>
[Ctrl+A 全选 注:引入外部Js需再刷新一下页面才能执行]
