html px em pt长度单位代码实例

编辑代码

<!DOCTYPE html> 
<html xmlns="http://www.w3.org/1999/xhtml"> 
<head> 
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> 
<style>
.manongjc-px{ font-size:12px} 
.manongjc-pt{ font-size:12pt} 
.manongjc-em{ font-size:2em} 
</style>
</head> 
<body> 
<div class="manongjc-px">我是码农教程</div> 
<div class="manongjc-pt">我是码农教程</div> 
<div class="manongjc-em">我是码农教程</div> 
</body> 
</html>