In this scenario, you are developing a website offline and you also have an online copy. Now for some reasons, you have
different logins for the database.
Some people will create user accounts for the database so that the same username and passwords will exist for the database
on the internet and local servers. Some will change the username/password whenever they upload it.
Anyone, they all get the same results.

I recommend that, if the username / password of your local and internet servers are different, try out this script.

connect.php

<?php
function sonline() {if ($_SERVER['SERVER_NAME']=="localhost"||$_SERVER['SERVER_NAME']=="127.0.0.1"||strtolower($_SERVER['SERVER_NAME'])==strtolower(getenv('COMPUTERNAME'))) {return false;} else {return true;}}

if(sonline()) {
//internet server config
$username="internet";
$password="google";
} else {
//local server config
$username="root";
$password="password";
}

$link = mysql_connect('localhost', "$username", "$password";
if (!$link) {die('Could not connect to mysql server. Check your account settings! ' . mysql_error());}

mysql_select_db("dhtmlproject",$link) or die ("Could not select database";
?>

I must quickly point out that the method is not fool proof. Because some servers make use of 127.0.0.2 or any other one. Common one is localhost and also 127.0.0.1 But again, study the sonline function. So that if your server is different, just put the IP address there.
It is a very simple technique really - just might come in handy atimes.

connect.php

<?php
function sonline() {if ($_SERVER['SERVER_NAME']=="localhost"||$_SERVER['SERVER_NAME']=="127.0.0.1"||strtolower($_SERVER['SERVER_NAME'])==strtolower(getenv('COMPUTERNAME'))) {return false;} else {return true;}}
if(sonline()) {
//internet server config
$username="internet";
$password="google";
$dbase="$username_dhtmlproject";
} else {
//local server config
$username="root";
$password="password";
$dbase="dhtmlproject";
}

$link = mysql_connect('localhost', "$username", "$password";
if (!$link) {die('Could not connect to mysql server. Check your account settings! ' . mysql_error());}

mysql_select_db("$dbase",$link) or die ("Could not select database";
?>

This modification is for some servers that when you are online, the name of the dbase will the the username_dbase.
Whatever the kind of server u are using, u can alwayz modify it to work.