Cannot modify header information [duplicate]

Answer 1

Take out the echo calls, you can't send information to the browser before the headers.

You can try something like this to still show if an error happens:

if(!$retval) {
    echo "Unsuccessfull " . mysql_error();
}

Answer 2

If you change the headers you cannot output any text prior to to the header command otherwise the headers will already be sent.

ie.

if($retval) {
    echo "Successfull";
} else {
    echo "Unsuccessfull " . mysql_error();
}

Is outputting text before you change the headers.

Answer 3

Use Output Buffers: http://php.net/manual/en/function.ob-start.php

ob_start();

at the start and

ob_end_flush();

at the end.

Answer 4

Use:

<meta http-equiv="Refresh" content="0;url=http://www.example.com" />

Answer 5

What I generally recommend for situations like this, is save all output to the end, as gmadd mentioned, you can do the ob_start, but I prefer to store the data in a string without having to add the extra code (I know you can also designate this in the .htaccess file, I would go that route over adding the actual ob_start items).

What I would do:

$display = ""; // initiate the display string 
// etc doe here
if($retval) {
    $display .= "Successfull";
} else {
    $display .= "Unsuccessfull " . mysql_error();
}

// end of the script right before ?>
echo $display;
?>

The ob_start method works and if you want to go that route, you can add this in the .htaccess file (given that allowoverride is set in your apache setup):

php_value output_buffering On

Again I still recommend the $display storage method, but that is my personal opinion.