How to grab AD credentials from client machine in a web application?

Question

Is it possible to grab activedirectory credentials for the user on a client machine from within a web application?

To clarify, I am designing a web application which

Answer 1

Maybe .NET has a more direct way to do it, but with PHP I just access our Active Directory server as an LDAP server.

I'm not sure what adjustments to the server are required to do this. I didn't setup the server, I just query it. I'm not suggesting you use PHP either. I just find it easier to deal with LDAP then trying to tie directly into Active Directory.