How to redirect to squid login web page when internet access

Hi ,
I am new user.
As you know when acl is defined in /etc/squid/squid.conf file according to its http_access users are able to access internet.
Before that .htaccess asks them to access internet.
It is fine.
I saw in some customised linux servers in place of .htaccess login ,html web page login is asked (by squid server ) to user while first time internet access and also
it might be worked with sessions .
I want to know how it can be achieved
Do you anybody have an idea???

Hi Anyone has any idea about this.

How to make home page / login page for squid access users in linux when they come to first time internet access.
I am looking for this solution for a long time
Thanks for any suggestions !!!