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How do I enable HTML5? I disabled it or blocked it by accident.

  • 2 回覆
  • 4 有這個問題
  • 8 次檢視
  • 最近回覆由 cor-el

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All the videos are blocked. For example, Youtube and Facebook videos. It only shows a black screen. Plus, only Flash works for now.

All the videos are blocked. For example, Youtube and Facebook videos. It only shows a black screen. Plus, only Flash works for now.

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install Flash plugin... such as adobe flash plugin

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You can check if there are media.*.enabled prefs that show user set (bold) on the about:config page.

You can open the about:config page via the location/address bar. You can accept the warning and click "I'll be careful" to continue.

Use the Search bar at the top of the about:config page to locate preferences more easily: media.*.enabled


Start Firefox in Safe Mode to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem.

  • Switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance
  • Do NOT click the Reset button on the Safe Mode start window