http in web browser address bar

Question

If we type a domain name in a web browser address bar, how will it discover the correct protocol for that domain ?

Example:
If we type linkedin.com in a web browser address bar, how does it know to add http://.....
--> ex : http://linkedin.com/ .......

Also, if we didn't mention ftp it will automatically add ftp://......

How does this all work ?

Answer 1

Different browsers implement this functionality in different ways.

Firefox: http://support.mozilla.com/en-US/kb/Location+bar+autocomplete

Chrome: http://www.google.com/support/chrome/bin/answer.py?hl=en&answer=95440

IE: http://support.microsoft.com/kb/221754