[RESOLVED] Form Field loses value on submit

[obrienkev]

Hi all,

I have a form that contains a hidden field. The hidden field's value is got once the user clicks a link on the previous page...

<a href="module/index.php?id='.$module_ID.'">Click Here</a>

Then on form page I get that variable...

$class_ID = $_GET['id'];

and create hidden field...

<input type="hidden" name="module" id="module" value="<?php echo $class_ID ?>" />

When I submit the form the code checks for errors. If any error it displays a message and the form again.

However, now the hidden field has lost its value.

How can I fix this?

Thanks.

Kevin.

[tsinka]

Hi,

please post the relevant code.

Thomas

[HeyRay2]

Depending on the method you are submitting your form that hidden value will exist in either...

$_POST['module']

or

$_GET['module']

If you are redirected back to your form, you will need to assign one of the corresponding values above to your $class_ID variable...

$class_ID = $_POST['module'];

or

$class_ID = $_GET['module'];

That should keep your hidden value populated.

[smartguyin]

Your Code :

<input type="hidden" name="module" id="module" value="<?php echo $class_ID ?>" />

change to <?php echo $class_ID; ?>

I think the only problem is that semi-colon correct it and try me it works or not..

[Installer]

The manual says:

The closing tag of a block of PHP code automatically implies a semicolon...

[HeyRay2]

In the line of code...

<input type="hidden" name="module" id="module" value="<?php echo $class_ID ?>" />

The use of the semicolon is optional.

The main problem is that the value in question gets passed around and reassigned to different variable names over and over again.

The variable in question first starts out as $module_ID, is then assigned to $GET['id'] from the URL, which in turn gets assigned to $class_ID. When the form is submitted, that value is now assigned to the $GET['module'].

When the form is reloaded it's expecting to reassign $class_ID from the $id variable, which only existed when the page was accessed by way of a URL, not a form submission. The code is looking for a variable that does not exist after the form is submitted.

Besides using my suggestion above, a more consistent method would be:

The hidden field's value is got once the user clicks a link on the previous page...

<a href="module/index.php?class_ID='.$module_ID.'">Click Here</a>

Then on form page I get that variable...

$class_ID = $_GET['class_ID'];

and create hidden field...

<input type="hidden" name="class_ID" id="class_ID" value="<?php echo $class_ID ?>" />

[obrienkev]

Thanks guys. This seems to work...

<input type="hidden" name="module" id="module" value="<?php if(isset($module_ID)){ echo $module_ID; } else {echo $class_ID;} ?>" />

[HeyRay2]

Based on link you said users would click on:

<a href="module/index.php?id='.$module_ID.'">Click Here</a>

The following code will never show your hidden value:

<input type="hidden" name="module" id="module" value="<?php if(isset($module_ID)){ echo $module_ID; } else {echo $class_ID;} ?>" />

This is because $module_ID never gets set on this page, only on the page the user came from. The page that contains your hidden field will only know the variable $id unless you change your link to read as below:

<a href="module/index.php?module_ID='.$module_ID.'">Click Here</a>

You've made your code too hard to debug by changing your variable name over and over.

While your change may work for now, the inconsistency of your code will probably just cause you more confusion down the road.

Just my 2 cents.

However, I'm glad you got your code working... 🙂