How to handle form reloads
 

Hi,

I have a form that submits data to a script that adds the information to a table and then the script displays the added information on the screen. Now, if the user hits the "Refresh" button on the browser the script is executed again and another record gets added with the same information.

I was wondering how to go about handling this issue so that if the user hits "Refresh" the script will not do anything.

When the user submits the form, return the data with a hidden value. Check for that hidden value when the form is submitted. Then simply don't update the data, just return what was sent.

That won't work. The hidden variable will be available for the next page, not the page they submitted. Or if you're talking about it being there from the start, that wont work either, as the hidden variable would be resubmitted as well.

Set a cookie when it's submitted. Then, check if the cookie is set. You could also use sessions, or checking if the submitted data to see if a similar data set is already in the database or was just submitted.

I always check to see if the database already has a set of matching records, assuming your input contains 1 piece of data that always has to be unique, a username for instance), then use that.

A cookie would also work, BUT, if someone submits then deletes their cookies and refreshes, it would most likely be entered again.

Why don't you have a page that scripts goes to, this page will update the table(s) then this page will go to another page where you get information from the table and display it. That way if they do decide to refresh only the get data operations will recur.

Thanks I was thinking about that too but I wanted to try and accomplish it with as few pages as possible.

Not only that, but they could hit the back button and resubmit the form data on the transfer page.

Yes it would. If you set a hidden value to false on the page, and submit it, all you have to do is test the value. If it comes out false, you know it's the first submission, so you process it. But then when you redisplay the page, just set that hidden value to true. Therefore, it won't be processed again. If it test true on the update page, just redraw the data again. Same effect as the cookie, sort of, but won't last if you close your window. It also comes down to how you program it. Cookie would probably be best though.

I think Booooze idea would work just fine, for instance here's a sample instead of using a hidden variable using the $_GET superglobal:This way the user has to consciously click to get to the submission form and submit data, and its still the same page. So even if they keep refreshing no new data is passed.

could you give an example perhaps?

Here's what I'm thinking based on this:
[php]<?php
if (isset($_POST['test']) && $_POST['test'] == 'false')
{
// process form
// to know the difference between whether it was the first submission or
// the second submission, you'd have to check something such as the database
// otherwise, there's no difference
}
<form method="post">
<input type="hidden" name="test" value="false">
<input type="submit" name="submit" value="Submit">
</form>[/php]