[RESOLVED] Warning: Cannot modify header information - ...

[Old_Fool]

Hi, I know nothing about PHP. All I know is basic HTML. But I want a contact form on my website and finally found this PHP form:
http://www.html-form-guide.com/files/email-form/php-form-to-email.zip

I uploaded the folder to my webspace (only changed the email address in the .php file) and tested it. It worked fine.

I managed to incorporate the whole thing into my website. But when I clicked 'Submit', I got an error saying:

error; you need to submit the form!
Warning: Cannot modify header information - headers already sent by (output started at /www/htdocs/my-webspace-name/contact/form-to-email.php:4) in /www/htdocs/my-webspace-name/contact/form-to-email.php on line 34

But I received the form email despite the error message.

When I removed

if(!isset($_POST['submit']))
{
echo "error; you need to submit the form!";
}

from the form, it worked fine again and the thank you page came up.

1st Question: Does anybody know why this is happening?
2nd Question: What does - if(!isset($_POST['submit'])) - do and do I actually need it for any security reasons, or can I just delete it?

My site is hosted on a Linux server, if that makes any difference.

Remember, I know nothing about PHP and using 'Old Fool' as a username isn't much of an exaggeration. Please take it easy on me.

Thanks, Robert

[m_tt]

The error is being triggered by the echo. You cannot output anything to the browser before sending header()

I'm guessing your form is supposed to have an input with a name of "submit" e.g.

<input type="submit" name="submit">

[Old_Fool]

Many thanks M@tt for pointing me in the right direction. When I checked for <input type="submit" name="submit">, I noticed that one submit was spelled with a capital letter and remembered that I read somewhere that PHP is case sensitive. It finally works!

Thanks again, Robert