案例：html案例     状态：可编辑再运行    进入竖版
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<!DOCTYPE html>
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<html>
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<body>
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​
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<video width="420" controls>
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  <source src="/img/movie.mp4" type="video/mp4">
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  <source src="/img/movie.ogg" type="video/ogg">
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 Your browser does not support the video tag.
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</video>
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​
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</body>
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</html>