PHP basic authentication set up

Thank, dr_dedo. but I prefer to use $_SERVER['PHP_AUTH_USER'] and $_SERVER['PHP_AUTH_PW'] without session

and generate query from a mysql table that contains user id and password. comparing $_POST variables with user id and password at the query.  I made the following code and it works well at a previous server, but I've changed a new server and it does not work on it.

So, I guess probably some setting problems on Apache and PHP.

Do I need to set anything on PHP and Apache when I use $_SERVER['PHP_AUTH_USER'] and $_SERVER['PHP_AUTH_PW'] on them ??

I made a simple mistake on $_SERVER['PHP_AUTH_PW']. I wrote not $_SERVER['PHP_AUTH_PW'] but $_SERVER['PHP_AUTH_PWD'] .

Anyway, thanks both guys....
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echo "THANKS";
echo "<BR />";
}
Best Regards, portal123