LDAP athuntication - Implementing digest authentication

[visit2siva]

we are working interanet site (php,apache,mysql,Xampp,winXP) and need to login using ldap Authentication through apache Using Digest Authentication (like digest authertication implemetion in IIS).
I did already classic LDAP authentication/User Interface, it works fine. But my client need login authentication called by apache server automatically when page is load.(auto popup window ask userid,pwd,domain).
Anybody has idea about it, pls share your experiece with me( code also).

Thanks in advance.

Regards

Shiva