Hi everyone. I got a html webpage and I need to create a Database with users and passwords (typical). I've tried so many times to connect with the MSSQL database with a PHP Script without success... The MSSQL database is hosted in 1and1 servers (and the complete webpage). I've tried different codes but any worked right.

A button in the html webpage executes the PHP Script, it executes right but the browser shows this error
Code:
Fatal error: Call to undefined function mssql_connect() in E:\kunden\homepages\13\d436936547\www\conec.php on line 2
Does anyone know how to RIGHT connect with a MSSQL database with PHP Script.
I've thought that the error could be in the server security from 1and1 or protected ports or something.
Can anyone helpm me?

Thanks.