List of some popular shortcut  for easy net surfing which work with various browser. You can understand with these example:

www.example.com
Type only example in address bar / Location bar then press Ctrl + Enter and you will get www. & .com automatically
Work with – Firefox , opera , Internet Explorer -6,7,8 , Google Chrome , Safari

www.example.net
Type only example in address bar / Location bar then press  Shift + Enter and you will get www. & .net automatically
Work with – Firefox

www.example.org
Type only example in address bar / Location bar then press Ctrl + Shift + Enter and you will get www. & .org automatically
Work with – Firefox