How to block websites on Firefox, Opera, Safari, IE?

How to block websites on Firefox, Opera, Safari, IE?
I'll explain how to block a website without using any software.
This will be very helpful for parents who would restrict Internet access rights for their children
The first one please open the folder C: \ WINDOWS \ system32 \ drivers \ etc, inside that folder is a file named "hosts" double-click the file "hosts" and open the file with notepad. The trick with the re-name and then add the extension. Txt, ignore the warning click OK, then
Once open in it should have text like this:
127.0.0.1 localhost
Well, after that just add to the website below you wish to block, but first you must add the digits of this number (see examples below) before the address of the site you want to block, for example www.you.com and www.me.com, thereby becoming like this:
127.0.0.1 localhost
127.0.0.2 www.you.com
127.0.0.3 www.me.com