Internet Explorer along with other browsers have one thing in common for sure that if we only give the URL of the site and press Ctrl + Enter, http://www and .com will be added before and after the text in the address bar respectively.
This is a great feature since it prevents us from typing the www and .com in the site URLs. But if you wish to change it for your purposes, then it is very easy as well.
1. Open the Registry editor and navigate to the following key HKEY_CURRENT_USER\Software\Microsoft\Internet Explorer\Toolbar.
2. Create a key there under toolbar key named QuickComplete (as shown)
3. In the right side of this key, create a String Value with the name QuickComplete with the value http://www.%s.net
4. %s signifies that whatever be the address, it will be inserted in between the www and .net
5. Similarly you can change to any extension instead of .net
6. Example: if you put the value http://www.%s.abc then on hitting Ctrl + Enter the extension abc would be produced.
Note: Only works in Internet Explorer