<?php
$mssqlHost = "hostname\\SQLEXPRESS"; #It is MSSQL Instance name
$mssqlUser = 'sa';
$mssqlPass = '1234abcd';
$mssqlDB = 'yourdb';
$s = mssql_connect($mssqlHost,$mssqlUser,$mssqlPass) or die('Could not connect to SQL Server on '.$mssqlHost.' '. mssql_get_last_message());
echo $s;
?>