Whitelist for Chrome automatically blocks all pages from any website that is not in your list of allowed websites. Create your own 'whitelist' of safe websites, and this extension will automatically block all pages from any other website that is not in that list. If you only specify the domain of the website, its subdomains will also be allowed. That is, if you add 'google.com', you WILL be able to access 'mail.google.com', and 'maps.google.com'. When installing Whitelist for Chrome, your browser will warn you that this extension can access your data on all sites, and your browsing history. These permissions are required to block pages when you are browsing.