Do you want to silence webpages that automatically start playing audio or video as soon as you open them? This can be especially tricky if you've opened several tabs and aren't sure where the sound is coming from.
The tab that's sounding off should display a speaker icon. Simply click on the speaker icon to mute the sound or you can right-click on the tab and select 'Mute Sound'. To restore sound, simply click on the speaker icon again.