Prevent resubmit form after click “back” button

Question

I have 2 pages :

page1.php :
- has a form with text box and a \"submit\" button. Eg :

Answer 1

You can prevent the re-submission by implementing the Post-Redirect-Get (PRG Pattern).

Could be just a one-line if you've got the http_redirect function:

http_redirect("page2.php");

Instead of your javascript echo.

If not, that are two lines:

header("Location: http://example.com/page2.php");
exit;

Replace example.com with site's your hostname.

Related: Back button re-submit form data ($_POST); I am confused about PHP Post/Redirect/Get

Answer 2

Can you do it via an Ajax call instead? No action on the form, and the submit will call a the Ajax function. The Ajax call will execute the query, and provide a response (you can just echo a result), and you can then provide dynamic feedback based on the result. You'd never leave the page.

<form id="thisForm">
...form input fields...
<input type="button" onclick="return submitForm('thisForm')"/>
</form>

function submitForm(formId) {
    $.ajax( {
        type: "post",
        url: 'page2.php',
        data: $('#' + formId + ' input').serialize(),
        ... any other Ajax parameters...,
        success: function(data) {
        }
    });
    return false;
}

Answer 3

Add this code in the page that is showing as offline when the user clicks the back button:

<?php
 session_start();
 header_remove("Expires");
 header_remove("Cache-Control");
 header_remove("Pragma");
 header_remove("Last-Modified");
?>

Answer 4

Rather than

echo '<script language="javascript">window.location="page2.php";</script>';

you should use the header() function to redirect your user after the submission.

So in psuedo code,

click submit on page.php action page1.php page1.php submits data to database calls

header('Location: http://example.com/page2.php');

This should prevent your clicking back problem

Answer 5

One way is to submit the Formdata via Ajax to a remote Script and if the Query returns success you can jump the a "Thank You" Page. So the User can hit the Back Button and the "Reload" Request doesn't pop up.

Hope the Idea helps you

Answer 6

Create a Session like shown here

You should use session and validate the user from every page and you will amaze how SESSION works! AMAZING!