有没有办法使用HTML5< video>标签？
如果这是不可能的，有谁知道这个决定是否有理由？
解决方法
HTML 5没有提供使视频全屏的方法，但是并行
Fullscreen specification提供requestFullScreen方法，该方法允许任意元素(包括< video>元素)全屏显示。
它有experimental support in a number of browsers。
原始答案：
从HTML5 spec(写作时：09年6月)：
User agents should not provide a
public API to cause videos to be shown
full-screen. A script,combined with a
carefully crafted video file,Could
trick the user into thinking a
system-modal dialog had been shown,
and prompt the user for a password.
There is also the danger of “mere”
annoyance,with pages launching
full-screen videos when links are
clicked or pages navigated. Instead,
user-agent specific interface features
may be provided to easily allow the
user to obtain a full-screen playback
mode.
浏览器可以提供用户界面，但不应提供可编程的。
请注意，上述警告已从规范中删除。