The default page in IIS, i.e. And an opera showing the right, but others are not

Question

I use Windows 7 bit 64. Opera and IE show the correct default page as: // localhost /, but GoogleChrome and FireFox try to show some other page that is currently missing from wwwroot inetpub.

I thought that FireFox and Chrome might try to show this page from some other server program, but when I removed wwwroot from my computer, they stopped showing any page as: // localhost.

I did not find any logic for the above case, kindly help me find out why FireFox and Chrome do not show the logically expected default page in IIS as: // localhost.