Header vs form action problem

[sciwaysoft]

I have a form which gets input from the use and in this form the action is

action="<?=$_SERVER['PHP_SELF'] ?>"

I have a php code which checks if the use has input the valid data and then if all is ok I have use the header function to redirect window to a page which has the code to submit this data to a data base and displays a ThankYou message.

My header function looks like

header ("Location: guesssubmit.php"); //line 66
exit;

But when I submit the form an erro is displayed

Warning: Cannot modify header information - headers already sent by (output started at
F:\Projects\mypro\site\guess.php:12) in F:\Projects\mypro\site\guess.php on line 66

[nemonoman]

This error means that you have "echoed" something before you try to execute the header command. You can execute header() all day long up until the point you "echo" or "print" anything.

[sciwaysoft]

Here is my code. you see echoing is necessory for me....

<?
 if ( $_POST['submit']){
 //--------------------------------------------------------------------
function is_valid_email($sender_mail) { 
if(ereg("([[:alnum:]\.\-]+)(\@[[:alnum:]\.\-]+\.+)", $sender_mail)) {
	return 0;
}
else{
    return 1;
}
}
$emailvalid = is_valid_email($_POST['email']);
//--------------------------------------------------------------------
if ($_POST['name'] && $_POST['email'] && $_POST['guess'] ){
 ////--------------------------------------------------------------------
 if ($emailvalid){
 echo "Email address is not valid";
 }else{
  ///--------------------------------------------------------------------
  if(is_numeric($_POST['guess']) and strlen($_POST['guess'])==3){ 
  header ("Location: guesssubmit.php"); /* Redirect browser */
  /* Make sure that code below does not get executed when we redirect. */
  exit;

  }else{ echo $_POST['guess'] . " is not a valid guess. <br> Read the rules please.";
  } 
  ///--------------------------------------------------------------------
 }
 ////--------------------------------------------------------------------
}else{
echo "You have'nt filled the form.<br>Plese fill all fields.";
}
}
?>

Any help further.....?

[laserlight]

I did some proper indenting of your code, and it becomes obvious that it isnt a logical problem of having to output text before a header().

Rather the problem probably lies in extra white space before the first <?php, which counts as output.

<?php
function is_valid_email($sender_mail) { 
	if (ereg("([[:alnum:].-]+)(@[[:alnum:].-]+.+)", $sender_mail)) {
		return 0;
	} else {
		return 1;
	}
}

if (isset($_POST['submit'])) {
	$emailvalid = is_valid_email($_POST['email']);
	if (isset($_POST['name']) && isset($_POST['email']) && isset($_POST['guess'])) {
		if ($emailvalid) {
			echo "Email address is not valid";
		} else {
			if (is_numeric($_POST['guess']) &&& strlen($_POST['guess']) == 3) {
				// Redirect browser
				header("Location: guesssubmit.php");
				// Make sure that code below does not get executed when we redirect.
				exit;
			} else {
				echo $_POST['guess'] . " is not a valid guess. <br> Read the rules please.";
			}
		}
	} else {
		echo "You have'nt filled the form.<br>Plese fill all fields.";
	}
}
?>