headers already sent error

[Royco]

hi all,
im doing a login.php page that analyses the user and password of a previous html form.

For this login to analyse the user/pass, it must connect to a database and use a "require_once" and a "include" in its code.


when i run this login on my computer, it works fine. But when i use it on the online server, i get the:

" Warning: Cannot modify header information - headers already sent by (output started at /home/rodrigopitta/www/teste/main.php:17) in /home/rodrigopitta/www/teste/login.php on line 21 "

main.php is the file that is "required_once"

i also have removed any blank spaces before the <?php and after the ?>....

must i delete the require_once or include files and make a direct connection to the database on every php page that requires a "header("Location: $header_login");" ?

what is the best way to redirect a page once the user/pass returns true? should i continue to use the headers method?

thanks everyone.

[toplay]

You can't have any HTML, JS, etc. even before the <?PHP tag. Check the required/included file also has no spaces, HTML, JS, etc. before issuing the header().

This has been asked to death. Please check these:

[a href=\"http://www.phpfreaks.com/forums/index.php?showtopic=37442\" target=\"_blank\"]http://www.phpfreaks.com/forums/index.php?showtopic=37442[/a]

[a href=\"http://www.phpfreaks.com/forums/index.php?showtopic=31047\" target=\"_blank\"]http://www.phpfreaks.com/forums/index.php?showtopic=31047[/a]