How does HTML video tag prevent users from downloading videos?

How to prevent downloading HTML5 videos from web pages?

Many websites want to protect their video content and prevent users from downloading at will. This article explores how a website prevents users from passing HTML5<video></video> Tag download videos, and the technical principles behind them.

Recently, when I tried to use the browser plug-in to download B station videos, I found that even if I got the MP4 video link, I could not download it directly. The browser prompted "The file cannot be extracted from the website", and only HTML files were saved. Further investigation found that the video link needs to contain the correct Referer information, otherwise the server will return a 403 error. This reveals how the website restricts video downloads.

<video></video> The tag itself does not have the function to prevent downloading. The mechanism for blocking downloads mainly depends on server-side configuration and front-end JavaScript code. Specific methods include:

1. Server-side Referer verification: The server will check the Referer field in the HTTP request header. If the Referer information does not meet expectations (for example, not from the website), the server will deny access, returning a 403 error. This is a common anti-theft chain mechanism.

2. Front-end JavaScript restrictions: Websites may use JavaScript code to disable the right-click menu, hide or modify the video URL, or dynamically generate video playback links to increase the difficulty of downloading.

3. Video encryption and dynamic loading: Some websites use video encryption technology, or through dynamic loading technology, making the real URL of the video difficult to obtain, thereby preventing direct downloading.

While these methods can effectively prevent most download behaviors, some professional video downloading tools or plug-ins may still bypass these limitations. The author tried to use parsing tools and found some high-definition video links, but due to the lack of appropriate tools, it was ultimately unable to download successfully.

In summary, preventing users from downloading videos is not<video></video> The function of the tag itself is the result of the joint action of server-side and front-end technologies. To download protected videos, you may need to use special tools or plug-ins.

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