Prevent form from being submitted twice

Question

I have a simple php form, like this:

<?php

if(isset($_POST['myform']))
   // email...
else
   // display form

the problem is that if I refresh the page after I submit the form, it gets submitted twice. How can I prevent this from happening?

Answer 1

You should perform a REDIRECT to a page with a message that the data was inserted... and a back button to go to the form again (if you want to)...

To redirect using PHP use the header function:

header('Location: http://www.example.com/');