用纯css画个三角形以下是源代码：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "<a href="http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd</a>">
<html xmlns="<a href="http://www.w3.org/1999/xhtml">http://www.w3.org/1999/xhtml</a>">
<head>
<title>用纯css画个三角形</title>
</head>
<body>
<style type="text/css">
.rightdirection
{
width:0;height:0;
line-height:0;
border-width:20px;
border-style:solid;
border-color:transparent transparent transparent #A9DBF6;
}
.bottomdirection
{
width:0;height:0;
line-height:0;
border-width:20px;
border-style:solid;
border-color: #A9DBF6 transparent transparent transparent;
}
.leftdirection
{
width:0;height:0;
line-height:0;
border-width:20px;
border-style:solid;
border-color: transparent #A9DBF6 transparent transparent;
}
.topdirection
{
width:0;height:0;
line-height:0;
border-width:20px;
border-style:solid;
border-color: transparent transparent #A9DBF6 transparent;
}
</style>
<div></div>
<p>
<div></div>
<p>
<div></div>
<p>
<div></div>
</body>
</html>
画个小三角形
<style>
#jb51_a{ border-top:10px solid #FFFFCC;
border-left:10px solid #FF3300;
border-bottom:10px solid #FFFFCC;}
</style>
<div id="jb51_a"></div>
以下代码兼容IE6：
<style>b.sanjiao{
display:inline-block;
width: 0;
height: 0;
border-width: 10px 10px;
border-style: dashed dashed solid dashed;
border-color: transparent transparent #ff0000;
font-size: 0;
line-height: 0;
-moz-transition: -moz-transform .2s ease-in;
-o-transition: -o-transform .2s ease-in;
transition: transform .2s ease-in;
vertical-align:text-top;
margin-left:5px
}</style>
<b></b>