Difficulty unsetting checkbox elements via session controls

[Sylvian Stone]

Hi there - I'm experiencing a very frustrating problem with an
application that submits POST info to a session control file which
then echo's it back to the controls if the page is returned to.

This works fine, except for check boxes - once it is checked, if I
then then return and uncheck it, then again return to the page later
on, the session still marks it as checked.

The code on the main pages is:

<input name="withdrawa ls_taken_10" type="checkbox" value="checkbox "
<?php if (isset($_SESSIO N["withdrawals_ta ken_10"])) {echo 'checked';}
else {echo '';} ?>>

The code on the control page is:

foreach($_REQUE ST as $key => $val) {
$_SESSION[$key] = $val; }

....quite straightforward stuff, but once a checkbox is registered as
set, why does it not register it as unchecked- especially if I leave
them unchecked from the outset, the session will correctly show it as
unchecked.

Hmmm.......help .....

Thanks
Sylvian.

[Pedro Graca]

Re: Difficulty unsetting checkbox elements via session controls

Sylvian Stone wrote:[color=blue]
> ...quite straightforward stuff, but once a checkbox is registered as
> set, why does it not register it as unchecked- especially if I leave
> them unchecked from the outset, the session will correctly show it as
> unchecked.[/color]

$_REQUEST will only have the selected elements in it.
To clear the unselected elements you have to do it manually.
Once you receive a checked value and put into into the session variable,
with your current code there is no way it gets reset: the $_REQUEST
array will never have the $key to an unchecked checkbox.

#v+

<?php
$_SESSION['cbox1'] = '';
$_SESSION['cbox2'] = '';
// ...
foreach ($_REQUEST as $key => $val) {
$_SESSION[$key] = $val;
}
?>

#v-


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[Sylvian Stone]

Re: Difficulty unsetting checkbox elements via session controls

Hi,

The suggestion you gave below seems to have the opposite effect - in
that every single checkbox becomes set when I return to the page, even
if most were unchecked before the form submission.

Sylvian.

Pedro Graca <hexkid@hotpop. com> wrote in message news:<btjd2g$7s 9h2$2@ID-203069.news.uni-berlin.de>...[color=blue]
> Sylvian Stone wrote:[color=green]
> > ...quite straightforward stuff, but once a checkbox is registered as
> > set, why does it not register it as unchecked- especially if I leave
> > them unchecked from the outset, the session will correctly show it as
> > unchecked.[/color]
>
> $_REQUEST will only have the selected elements in it.
> To clear the unselected elements you have to do it manually.
> Once you receive a checked value and put into into the session variable,
> with your current code there is no way it gets reset: the $_REQUEST
> array will never have the $key to an unchecked checkbox.
>
> #v+
>
> <?php
> $_SESSION['cbox1'] = '';
> $_SESSION['cbox2'] = '';
> // ...
> foreach ($_REQUEST as $key => $val) {
> $_SESSION[$key] = $val;
> }
> ?>
>
> #v-[/color]

[Pedro Graca]

Re: Difficulty unsetting checkbox elements via session controls

Sylvian Stone wrote:[color=blue]
> The suggestion you gave below seems to have the opposite effect - in
> that every single checkbox becomes set when I return to the page, even
> if most were unchecked before the form submission.[/color]

Sorry for the mess (I put myself into). I didn't pay attention to all of
your code.

Problem is that $_SESSION[] is tested with isset().
With my suggestion all of the relevant $_SESSION[] are set, but their
value is '' (the empty string).

If you change the previous code from
if (isset($_SESSIO N[...]))

to
if ($_SESSION[...] != '')

I think it will be ok.


All of the $_SESSION is guaranteed to exist, so there should be no need
to test with isset(), but to be safer you may want to do
if (isset($_SESSIO N[...]) && $_SESSION[...] != '')
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