在线运行代码 - 菜鸟教程

<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8"> 
<title>菜鸟教程(cainiaoplay.com)</title>
<style>h1 {letter-spacing:2px;}
h2 {letter-spacing:-3px;}
</style>
</head>

<body>
<h1>This is heading 1</h1>
<h2>This is heading 2</h2>
</body>
</html>

源代码

动行结果