HTML 代码:
<!DOCTYPE html>
<html>
<head>
<style>
h2 { position:absolute;}
</style>
</head>
<body>
<h2>This is a heading with an absolute position</h2>
</body>
</html>
问题:
如果我删除这一行:position:absolute;
,文本<h2>...</h2>
会向上移动,为什么?