Muter

Motor is a Mozilla Firefox plugin that lets you use your browser (and your browser only) in one click.

After you install it, a small deer icon appears in the browser bar below. To maintain the volume of the rest of your computer, just click it to mute your browser to return to normal, click again

You can change between two different icons, and, if you want, you can set up a keyboard shortcut too. In this way, to mute your browser, you only need to use shortcut keys.

Muter is a very useful plugin that has ads with sound that can quite be quite annoying now. With this plugin, you can solve this problem quickly and easily.