redirect if variable is not set

I have a simple form for leads, if can I redirect the mail.php page back to the form if a varialbe is not set?

 

Something like this should work

<?php
  if (!isset($_POST['variable_name'])) {
    header('Location: http://www.yourdomain.com/mail.php');
  }
?>

PHP:

 

You don't have to use the isset command, you could just say !$_POST['variable_name']

<?php
if(!$_POST['varible_name'])
      {
       header("Refresh: 0; url=http://siteurl.com/mail1.php");
      }
?>

PHP:

 

and this will work with any browser?

thansk a ton. sometimes things are more simple than i think

 

This is a server side redirect, browser types don't matter.

enjoy!

 

Beware of the headers already sent error that sometimes comes up. Just make sure you don't output anything before you issue a header redirect.