Trying to redirect page after form validation. but get error

[numerical25]

I have a page that submits users info. then it takes it to a page where it checks for validation. if validation is correct, it takes it back to the orginal page in which the form was submited with a defined session var.

When i run the page. I type in my information into the form and when i press submit. I get the error below
Warning: Cannot modify header information - headers already sent by (output started at C:\www\apache\htdocs\check.php:9) in C:\www\apache\htdocs\check.php on line 23

whats the problem ?

[NogDog]

As soon as your script output anything to the browser, either via echo(), print(), or anything else that prints out data; or by anything (including white-space) not within <?php ... ?> tags, then HTTP headers are output at that time. Once headers are sent, you can no longer call any PHP functions that affect headers, such as header() or setcookie().

The error message would seem to indicate that something at line 9 of your script has generated output, but later at line 23 you are doing something that tries to "modify header information".

[numerical25]

WOW lol. This seems pretty tricky. well here is my code

<?PHP session_start(); ?>
<?php if  ($_POST['loginName'] != "" && $_POST['password'] !=""){?>
	<?php require_once('Connections/ok.php');?>
			<?php 
			mysql_select_db($database_ok,$ok);
			$query = sprintf("SELECT firstName, loginName, passWord, USERID
						FROM users
				WHERE loginName = '%s'",mysql_real_escape_string($_POST['loginName']));
	$results = mysql_query($query) or die("Query failed ($query): " . mysql_error());
 	$check = mysql_fetch_assoc($results);

			  if (strcasecmp($check['loginName'],$_POST['loginName']) == 0 
			  		&& strcmp($check['passWord'],$_POST['password']) == 0
					&& !$check['passWord']== "" && !$check['loginName'] == "") {
					$_SESSION['user'] = array('firstname'=>$check['firstName'],'userID'=>$check['USERID'],'loginName'=>$check['loginName']); 
empty($_POST['loginName']); empty($_POST['passWord']); 
mysql_close($ok);
header('location: http://localhost/admin.php');} 
else {  header('location: http://localhost/admin.php'); }?>
<?php }?>

how do you go about fixing this ??? So it works. Is there a better method for redirecting pages ?? should I put head(); function inside an include ?? or what??

cause i want it to check my syntax before it redirects the page

[blackhorse]

<?php if ($POST['loginName'] != "" && $POST['password'] !=""){?>XX
XXX<?php require_once('Connections/ok.php');?>XX
XXXXXXXX<?php

Your codes may have spaces in the places I marked as XXX

Put all the codes in one
<?php
?>
block and try again, it might help.

[numerical25]

SOoooo??? in order to use a header() function. It has to be at the very top of the document and has to be in one php block ?? im a little lost.

[HalfaBee]

You need to remove whitespaces, eg space newlines etc.

<?PHP session_start(); ?>
<?php if  ($_POST['loginName'] != "" && $_POST['password'] !=""){?>
    <?php require_once('Connections/ok.php');?>
            <?php 

should be 

<?PHP session_start();
if  ($_POST['loginName'] != "" && $_POST['password'] !=""){
    require_once('Connections/ok.php');

This should remove all the whitespace and make it work.
You should really find a tutorial on code formatting.

http://www.phpcodingstandards.com/php/

[NogDog]

numerical25 wrote:

SOoooo??? in order to use a header() function. It has to be at the very top of the document and has to be in one php block ?? im a little lost.

Anything that is not inside of the <?php . . . ?> tags, including newlines, tabs, and spaces, as well as any other characters, will cause output to be sent to the browser, and as a side-effect headers will be sent. Therefore, you either need to (1) make sure that before you make your call to header() that there is no such output before it (nor any PHP functions that will send output); or (2) use output buffering functions as a way to work around this.

(1):

<?php  // make sure no spaces/newlines or any characters before this
// . . .
// any PHP code that does not cause output can go here
// . . .
header('Location: http://go.somwhere.else/');
exit;

(2):

<?php  // make sure no spaces/newlines or any characters before this
ob_start();
// do whatever you want, but nothing will get output until your script ends
// or until you "flush" the output buffer:
header('Location: http://go.somwhere.else/');
ob_flush();