如何在php中避免Form Re提交

Question

I have a form in dashboard.php to create invoice and this is submitted to invoice.php

Now my invoice.php inserts the Invoice and the customer into the database and then shows me a invoice order filling form.

if i refresh this page, it inserts a new invoice for the same customer, how do i avoid this.

I was reading that we could avoid it by redirection, but in my case how do i use it. Some thing like a PRG(post/redirect/get) how to use it?

Do i need to make an intermediate page before going to insert items to invoice

Answer 1

after successful form submission do a redirect to the same page and optionally indicate that the submission was successful

Example: invoice.php

if (count($_POST)) {

    if (/*post data is valid*/) {

        /*do whatever is needed*/
        header('Location: invoice.php?success');
    }
} else if (isset($_GET['success'])) {

     echo "Form successfuly submitted";
}