<!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>css3绘制三角形</title>
<style type="text/css">
div{
margin-bottom: 10px;
}
#SJX_UP{
width: 0px;
height: 0px;
overflow: hidden;
border-left: 20px solid transparent;
border-right: 20px solid transparent;
/*兼容IE6*/
_border-left: 20px solid #fff;
_border-right: 20px solid #fff;
border-bottom: 20px solid red;
}
#SJX_DOWN{
width: 0px;
height: 0px;
overflow: hidden;
border-left: 20px solid transparent;
border-right: 20px solid transparent;
border-top: 20px solid red;
}
#SJX_RIGHT{
width: 0px;
height: 0px;
overflow: hidden;
border-top: 20px solid transparent;
border-bottom: 20px solid transparent;
border-left: 20px solid red;
}
#SJX_LEFT{
width: 0px;
height: 0px;
overflow: hidden;
border-top: 20px solid transparent;
border-bottom: 20px solid transparent;
border-right: 20px solid red;
}
</style>
</head>
<body>
<div id="SJX_UP"></div>
<div id="SJX_DOWN"></div>
<div id="SJX_LEFT"></div>
<div id="SJX_RIGHT"></div>
</body>
</html>
20px哪里可以自行调节大小
