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Notice: Since Facebook changed their layout to a new, "photo-oriented" style, the interface may look different.
If you hate the sound you hear when you get a notification on Facebook, or if you're working but still want to occasionally look at your news feed without constantly getting distracted with new notifications, this is the way to turn it off, without closing the webpage.
First go to the Settings menu in the right corner and click on Account settings.
Then click on Notifications in the left sidebar.
Click on On Facebook
Check Play a sound when each new notification is received
Click on Save Changes
This post was last updated on March 5th, 2013.