A week after we broke the news that Mozilla was finally implementing audio indicators to show noisy tabs, Firefox Nightly has gained the new functionality. The feature shows a speaker icon if a tab is producing sound and a single click mutes (speaker icon gets crossed out) or unmutes the given tab.

Firefox development starts with Nightly builds, which consist of the latest Firefox code packaged up every night for bleeding-edge testers. It is then followed by the Firefox Developer Edition (or Aurora on mobile), which includes everything that is labeled “experimental.” After that, the code eventually finds its way to Beta and then finally Release for the broader public.

Here is a tab audio indicator and muting in action:

firefox_nightly_mute

The best part is that you can mute a tab without having to switch to it first. As shown in the screenshot above, I was able to click on the speaker icon to mute the YouTube tab without leaving the VentureBeat tab.

This functionality has been available as browser add-ons and extensions for a while, but users want it built into the browser. Back in February 2013, we first heard audio indicators were coming to Chrome, and indeed, the feature arrived in January 2014 with the launch of Chrome 32.

That said, while Chrome has had audio indicators for more than a year now, it still doesn’t let you easily mute tabs. The option is available in Google’s browser, but it’s not enabled by default (you have to turn on the #enable-tab-audio-muting flag in chrome://flags/).

Mozilla’s implementation works with all APIs that let you play audio (including HTML5 audio and video tags, Web Audio, and the latest Flash beta). The company wants to offer the indicator and muting functionality together, and the fact it has landed in Firefox Nightly means it will be on its way through the developer, beta, and release channels.

Still, Mozilla told VentureBeat last week there is no “estimated timeline” for when the feature will be available to all Firefox users. That said, it shouldn’t take longer than just a few months.