Automatically mutes the Twitch player when an advertisement started and unmute it once finished. You can also hide ads by setting disableDisplay to true.
< Feedback on Twitch - Mute ads and optionally hide them
If by that you're asking if you can do something else during an ad, like checking another tab, you sure can. I often have one or two streams on the side, and it's working perfectly.
Is it possible to switch tab if an ad starts playing?