Firefox add-ons can provide content filtering, but cannot prevent people from working around or disabling such filtering. Add-ons can be disabled within Firefox or manually deleted from the hard drive. If you need comprehensive content filtering that prevents potential workarounds, third party parental control software is suggested. A free Firefox add-on for content filtering by category, ProCon Latte, is available from: https://addons.mozilla.org/en-US/firefox/addon/1803