追求极致--纯css制作三角、圆形按钮，兼容ie6

参考了天猫、微博等网站的做法，用纯html和css实现，效果还是不错的。
以下是成果，兼容主流浏览器，包括ie6。
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"             "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">

<head>

<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />

<meta http-equiv="Content-Language" content="zh-CN" />

<meta name="Keywords" content="" />

<meta name="Description" content="" />

<title></title>

</head>

<style type="text/css">

*{margin:0; padding:0; list-style:none; font:normal 12px/150% 宋体; }

body{ padding:20px; }

.arrow{ margin-bottom:20px;  }

/* css三角形 */

.arrow,.arrow s { position:relative;  display:block; font-size: 0; line-            height: 0; width: 0; height: 0; border-color:transparent; border-style:dashed; border-width:5px; }

.arrowR,.arrowR s{ border-left-color:#aaa; border-left-style:solid; }

.arrowR s{ border-left-color:#fff; position:absolute; left:-7px; top:-5px; }

.arrowR:hover{ border-left-color:#f60;  }

.arrowL,.arrowL s{ border-right-color:#aaa; border-right-style:solid; }

.arrowL s{ border-right-color:#fff; position:absolute; right:-7px; top:-5px; }

.arrowL:hover{ border-right-color:#f60;  }

.arrowT,.arrowT s{ border-bottom-color:#aaa; border-bottom-style:solid; }

.arrowT s{ border-bottom-color:#fff; position:absolute; left:-5px; top:-3px; }

.arrowT:hover{ border-bottom-color:#f60;  }

.arrowB,.arrowB s{ border-top-color:#aaa; border-top-style:solid; }

.arrowB s{ border-top-color:#fff; position:absolute; left:-5px; bottom:-3px; }

.arrowB:hover{ border-top-color:#f60;  }

/* css圆形 */

.circle{ line-height:100%; overflow:hidden;  font-    family:Tahoma,Helvetica; font-size:18px; color:#aaa;  }

.circle:hover{ color:#f60;  }

/* 提示盒子 */

.tipBox{ width:200px; margin-top:10px;   }

.tipBox .hd{ height:5px;  position:relative;  }

.tipBox .hd .arrow{ position:absolute; top:-5px; left:10px; }

.tipBox .hd .arrow s{ top:-4px; }

.tipBox .bd{ border:1px solid #aaa; padding:10px;  -webkit-border-    radius:5px; -moz-border-radius:5px; border-radius:5px;  }

.tipBoxA .arrow s{ border-bottom-color:#f6f6f6;  }

.tipBoxA .bd{ background:#f6f6f6;  }

</style>

<body>

<a class="arrow arrowR"></a>

<a class="arrow arrowL"></a>

<a class="arrow arrowT"></a>

<a class="arrow arrowB"></a>

<a class="arrow arrowR"><s></s></a>

<a class="arrow arrowL"><s></s></a>

<a class="arrow arrowT"><s></s></a>

<a class="arrow arrowB"><s></s></a>

<a class="circle">•</a>

<div class="tipBox">

<div class="hd">

<s class="arrow arrowT"><s></s></s>

</div>

<div class="bd">

用css做的提示盒子，上三角是纯css，盒子圆角用到css3

</div>

</div>

<div class="tipBox tipBoxA">

<div class="hd">

<s class="arrow arrowT"><s></s></s>

</div>

<div class="bd">

用css做的提示盒子，上三角是纯css，盒子圆角用到css3

</div>

</div>

</body>

</html>