WhiteList

This extension enables you to control which sites can be visited in the browser. You have the option to use a whitelist, which blocks all sites not listed, or a blacklist, which allows all sites except for the ones you list.
When you install the extension, you will be asked to set an administrator password. This password will be used to change the blocking options in the future.
You can then go to the extension's options page, and select whether to enable blocking (it is disabled by default), whether to use a whitelist or a blacklist, and specify which URLs you want in the list. Click "save," and the sites will be blocked!