Web pages can automatically play audio thanks to HTML5, even if you’ve set Flash and other browser plug-ins to click-to-play. Most modern web browsers include an audio indicator that will show you which tab is playing sound. Most modern browsers also let you mute individual tabs.
This feature was available behind a hidden flag in Chrome for a while, and is now stable. Apple’s Safari was the first web browser that actually enabled it by default, and Mozilla is working on adding it to Firefox.
Google Chrome
This feature is now part of the stable version of Chrome and doesn’t require enabling any hidden flags to use. Just locate a tab playing audio — you’ll see a speaker indicator to the left of the “x” on the tab itself. Right-click the tab and select “Mute Tab.”
The audio indicator will turn to a crossed-out speaker icon, informing you that the tab isn’t allowed to play audio. Right-click it again and select “Unmute Tab” to change your choice.
You can also do this preemptively. Right-click any tab and you’ll be able to select “Mute Tab,” preventing audio from playing on that tab even before it starts.
Note that, unlike the way this feature worked when it was behind a hidden flag, you can’t simply click the speaker icon to mute and unmute a browser tab. Google was clearly worried people would accidentally click this, muting their tabs and being confused. Chrome developers argued against enabling this by default and only did so until Apple pulled the trigger in Safari.
Apple Safari
This is also possible in Safari — Safari was the first browser that made this feature available to all its users.
As in Chrome, you’ll see a speaker icon to the left of the “x” button on an individual browser tab when it’s playing audio. You can click the speaker icon to mute the tab, and click it again to unmute the tab. You can also right-click or Ctrl-click the tab and select “Mute Tab” to mute that individual tab.
Unlike in Chrome, there’s no way to preemptively mute a tab. This option is only available when a tab is already playing audio.
Mozilla Firefox
Firefox is on the verge of adding built-in audio indicators on its tabs and a way to mute them. According to the bug report, this feature should be part of Firefox 42. It’s part of the latest experimental “nightly” builds of Firefox, too.
It works similarly to Safari and Chrome. If a tab is playing audio, you’ll see an audio indicator to the left of the “x” button on the tab. You can click that little speaker icon to mute a tab or right-click the browser tab and select “Mute Tab.”
Like Chrome, Firefox also allows you to preemptively mute tabs before they start playing audio — just right-click a tab and select “Mute Tab.”
If you’re still using an old version of Firefox, you can do this by installing an extension like “Mute Tab.” However, this extension doesn’t work as well — it only works with HTML5 audio. Thankfully, it’s possible to prevent plug-ins from automatically playing by setting them to click-to-play in Firefox.
Microsoft Edge
Microsoft Edge does at least include audio indicators on its tabs. Unlike all other browsers, however, those audio indicators are located at the left side of each tab.
Edge doesn’t yet offer a built-in way to mute tabs, and it doesn’t support browser extensions. Browser extensions — or Microsoft itself — may one day bring this feature to Edge. For now, Edge is still stuck playing catch-up to the features offered by established browsers.
You can always mute your entire browser to prevent all web pages from playing audio until you change your mind — assuming you’re using Windows or Linux. On Windows, right-click the volume icon in your system tray, select “Open Volume Mixer” and use the mixer to mute the browser or at least lower its volume. On Linux, you’ll usually find this option in your desktop’s sound settings, too — it’s offered by PulseAudio. Mac OS X doesn’t offer this feature.