案例：html/html5 案例     状态：可编辑再运行    进入竖版
 运行结果　
​x
 
1
<!DOCTYPE HTML>
2
<html>
3
<body>
4
​
5
<section>
6
  <h1>PRC</h1>
7
  <p>The People's Republic of China was born in 1949...</p>
8
</section>
9
​
10
</body>
11
</html>
12
​