Hi
@shum, and welcome! I'm not sure what you mean.... websites and web browsers kind of go hand in hand.
1. Do you want to block "outgoing" activity... like keeping someone in your home or office from reaching a website, such as blocking access to pornography? Or...
2. Do you want to block "incoming" activity.... like restricting attempts to access your computer from the web, such as from hackers or some services that people use, like FTP or SSH or others like chat or messaging apps. Or...
3. Do you mean "ad blockers" instead of website blockers?
A good firewall is the typical tool for restricting incoming and outgoing activity, and it is not tied to your browsers. They work pretty well with their basic settings in Linux, but if you have special requirements, then they are probably not going to be newbie-friendly. So what is it that you really want to accomplish?