Extracting The Domain Name From A URL Without The Extension?

I am trying to extract the domain name from a url using javascript but having some problems.

This is what I have:

Code:
var publisherName = document.domain;
if(publisherName.indexOf('www')){
publisherName = document.domain.substr(3,document.domain.length);
}

But it is not working and I am not sure how to rid of the extension Basically, this is what I want: Whether the location being sub domain or not it need to get from somthing similar to[URL]...