PHP: Only Checked Checkboxes pass values

Seguer

Who was the genius that thought that up?

I have a script that dynamically generates checkboxes, called Active, to determine if an address is active or not. If it's checked, then the address is active. But, if you try to edit this address to make it inactive by unchecking the checkbox, it doesn't send the name of the checkbox and its value!

Is there a way around this besides having two checkboxes that toggle each other? (an Active and Inactive checkbox)

DrFrylock

It's been a while since I did this, but I'm pretty sure that browsers don't submit data for an unchecked checkbox. One thing you can do is to put a hidden field in the form with a name that's similar to the one with the checkbox and then you know if there was a checkbox there, but if you don't get a matching value, then you know that it was unchecked. So:

<input type="hidden" name="mycheckbox_hidden" value="doesntmatter"/>
<input type="checkbox" name="mycheckbox" value="something">

If you see a value for mycheckbox_hidden but not mycheckbox, then you know there was a checkbox called mycheckbox but it wasn't checked.

Seguer

Hmm.. I'd actually done that before I tried doing it this way, heh. But then I took it out as I figured "hey, that's just extraneous code!" but I guess it's not. Damn!

Thanks.

DrFrylock

Seguer wrote: »

Hmm.. I'd actually done that before I tried doing it this way, heh. But then I took it out as I figured "hey, that's just extraneous code!" but I guess it's not. Damn!

Thanks.

Well your other option is just to see if there's a value defined or not for a given name. Now if it's not, one of two things happened: the box wasn't checked, or there was no such checkbox in the form. There's no way to tell the difference, of course, and this assumes that you know the names of all the checkboxes in the form a priori, but if you know there was a checkbox there called "available" and there's no value for "available" then it wasn't checked.

Seguer

Yeah, unfortunately because they are dynamically generated, I'd have to somehow pass on a list of those in my POST stuff. I've pretty much got the other method working already though so thanks anyway!

SporkAndrew

If they're dynamically generated you can just pass a list of the checkboxes in a hidden variable:

<input type="hidden" name="checkboxes" value="checkbox_name_1|checkbox_name_2|[...]"/>

Then on the other side explode that value and check:

[php]
$checkboxes = explode("|", $_POST);
foreach ($checkbox as $check_name) {
if ($_POST[$checkbox]){
[...]
}
}
[/php]

Seguer

Could, but oh well. Already did it the other way. And that php code block looks horrible oO (the colours)

SporkAndrew

Oh dear God I just noticed that. I just wanted to press the fancy "php" button.

robotbebop

Also, in PHP, if you name checkboxes like <input type="checkbox" name="myboxes[]"> $_GET/$_POST/$_REQUEST["myboxes"] will be an array.

So if (!isset($_POST["myboxes"])) returns true then you know there aren't any checkboxes, and you don't have to deal with any nasty string parsing code

EDIT: Helpful hints, using $_REQUEST may be more convenient, but it is less secure. You can name ANY form input field like "foo[]" and get it back as an array

Seguer

Doh. I think I saw that array thing while I was researching the checkboxes, but I paid no attention to it.