代码：
<html><br>
<head><br>
<title>css圆角效果--网页特效/www.cnwebshow.com</title>
<meta http-equiv="content-type" content="text/html; charset=gb2312">
<style type="text/css">
div.RoundedCorner{background: #9BD1FA}
b.rtop, b.rbottom{display:block;background: #FFF}
b.rtop b, b.rbottom b{display:block;height: 1px;overflow: hidden; background: #9BD1FA}
b.r1{margin: 0 5px}
b.r2{margin: 0 3px}
b.r3{margin: 0 2px}
b.rtop b.r4, b.rbottom b.r4{margin: 0 1px;height: 2px}<br>
</style>
</head>
<body>
<div class="RoundedCorner">
<b class="rtop"><b class="r1"></b><b class="r2"></b><b class="r3"></b><b class="r4"></b></b>
<br>无图片实现圆角框<br><br>
<b class="rbottom"><b class="r4"></b><b class="r3"></b><b class="r2"></b><b class="r1"></b></b>
</div>
</body>
</html>