form validation with reference

[amos88]

hi

I went through the search engine and found some points but not exactly the ones I need ... (or understand ;-)

I want to validate if a person enters text in a form and which one he/she enters -> but I don't want to stay on the same page -> the results should be printed on a new page - ok:
what I have ...

<?
if($submit & (empty($aufgabennr)))
{
?>

<form method ="post" action="aufgabe.php">
Aufgabe Nummer: <input type ="Text" name="aufgabennr" size="10" >
<input type ="image" src="mehr.gif" name="submit" value="Aufgaben Nummer abschicken">
</form>

<?
}
else
header("Location: aufgabe.php");
?>

what I get is: Cannot add header information - headers already sent

any ideas ???
did I miss something

thanks

michael

[[deleted]]

You have to make sure that you print absolutely nothing before printing the header.
That also means that there may not be a single character outside of the <? ?> tags before the header statement gets executed.

[amos88]

ok - i removed everything - now the second page is loaded at once ... hmm - still an error in the code ?

m