First off there are over a hundred different browsers... Theres browsers on set-top tvs, browsers on mobile phones and palm pilots.. browsers on atari and amiga and mac and other computers.... each have lots of different browsers to choose from
You dont check them.. you dont need to.. You make your website correctly and it will work on all. You use validation software or websites to find if its fully accesible.. ie
http://validator.w3.org
It is NOTa legal requirement to ahve your website work in all browsers.