<!DOCTYPE HTML> <html> <head> <title>MSE: disabling via pref</title> <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script> <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" /> </head> <body> <pre id="test"> <script class="testbody" type="text/javascript"> SimpleTest.waitForExplicitFinish(); function test() { ok(!window.MediaSource && !window.SourceBuffer && !window.SourceBufferList, "MediaSource should be hidden behind a pref"); SimpleTest.doesThrow(() => new MediaSource, "MediaSource should be hidden behind a pref"); SimpleTest.finish(); } SpecialPowers.pushPrefEnv({"set": [ ["media.mediasource.enabled", false], ] }, test); </script> </pre> </body> </html>