console 命令行工具 X clear

console

<html>
<head>
<style>
h1.one
{
visibility:visible;
}
h1.two
{
visibility:hidden;
}
</style>
</head>
<body>

<h1 class="one">标题 一</h1>
<h1 class="two">标题 二</h1>

<p>标题二在哪儿？</p>

</body>
</html>