browser - Is there any way to block websites without Root access

I am searching for a way to block websites without having root access. Is there any way to do it? Any help will be appreciated.

Answer

^{Summed-up solution from above comments:}

You can use a filtering proxy like e.g. FilterProxy, which lets you define what URLs should be blocked. To prevent other users from simply disabling the proxy then, you could protect it using an app locker like e.g. App Lock.