FocusBlocker is a light-weight add-on that blocks time-wasting websites to help you focus on real work. FocusBlocker can give you flexible control over when you want to block, which is superior than a schedule-based approach is you have a flexible working schedule. Firefox version: https://www.crxsoso.com/firefox/detail/focusblocker-new/ How It Works --------------------------------------- 1. Set a timer, say 10 min. 2. Browse freely for 10 min. 3. When time is up, the blacklisted sites will be blocked for 50 min (configurable).