hostname is a property of both the Link and the Location objects and specifies the server name, subdomain and domain name (or IP address) of a URL. Assuming your current window to be the URL...

http://home.newco.com/products/enquiries.htm#local?email=name@otherco.com

...you could find out the hostname property as follows:

Code:
document.write(location.hostname)

Output:
home.newco.com

NOTE:

Although the hostname property can be set at any time, it is safer to set the href property to change a location.