How to deal with unchecked checkbox array value without javascripts? - php

Question

Suppose I have a form like this, where checkboxes are repeating fields:
<form action="" method="post">
<?php for($i=0; $i<3; $i++) { ?>
<input type="checkbox" name="ch[]" value="1">
<?php } ?>
<button type="submit" name="submit">submit</button>
</form>
I'm on WordPress and using custom meta boxes for dealing with it. So I declared the form within the callback function of the metabox, and receiving the values in another save function that's hooked with save_post and new_to_publish action hooks.
So what's happening: when I click on the button, the metabox callback submitted the form, and the hooked function receives it. (Can be visible at add_meta_box() WordPress Codex) Suppose my save function contains:
<?php
if( isset($_POST['submit']) ) {
$chb = $_POST['ch'];
$result = array();
foreach ($chb as $cb) {
$result[] = array( 'isactive' => $cb );
}
var_dump($result);
}
?>
It's showing that, checkboxes are not returning any value when unchecked. I considered all the server-side solutions mentioned here: Post the checkboxes that are unchecked
PROBLEM is, whenever the form is submitted, it's taking the checkboxes' values to an array(), so I can't check the array values like:
if( !isset( $_POST['ch'] ) || empty( $_POST['ch'] ) ) {
$chb = 0;
} else {
$chb = 1;
}
I also tried hidden field with 0 value, accompanied with array_unique(), but nothing seems work for me.
How can I deal with unchecked checkboxes in an array so that they can't be null, and my foreach can loop through all of 'em and store data accordingly, and correct?
I want to avoid JavaScripts solutions.

Answer 1

If you name the checkboxes with an index in them, like so:
<input type="checkbox" name="chk_<?php echo $i ?>" value="1">
Then you could loop through them like so:
<?php
$chkBoxes = array();
foreach ($_POST as $k => $v) {
if (strpos("chk_",$k) === 0) {
$cbIndex = str_replace('chk_', '', $k);
$chkBoxes[$cbIndex] = $v;
}
}
Then to test if a checkbox was checked and sent to the server, you could use:
<?php
if (isset($chkBoxes[$cbIndex]))
Remember - the value of the checkbox is only sent if it was checked: Does <input type="checkbox" /> only post data if it's checked?

Answer 2

Add a hidden field in the form with the number of checkboxes, and use the index $i for the array ch[]:
<form action="" method="post">
<input type="hidden" name="num" value="<?= $num = 3 ?>">
<?php for($i=0; $i<$num; $i++) { ?>
<input type="checkbox" name="ch[<?= $i ?>]" value="1">
<?php } ?>
<button type="submit" name="submit">submit</button>
</form>
Then:
<?php
if( isset($_POST['submit']) ) {
$chb = $_POST['ch'];
$num = $_POST['num'];
$result = array();
for($i=0; $i<$num; $i++) {
$result[$i]['isactive'] = isset($chb[$i]) ? 1 : 0;
}
var_dump($result);
}
?>

Answer 3

first of all i copied ideas from many people inside this forum! i only synthesized the way!
my function to get data from my base located inside the $anoigmata class:
function getall() {
$data = $this->_db->get('<table_name>', array('ID', '>=', 0));
$results = $data->results();
$rows = $data->count();
return array($results, $rows);
}
code inside the create function to save all the secondary options that are not presented on the site.
$fields_Κ = array('history' => serialize(array(
'checkboxes' => Input::get('checkboxes')
)),
);
$data = $this->_db->insert('ΚΕΛΥΦΟΣ', $fields_Κ);
return true;
the php-html code that shows the result
<form method="post">
<div class="form-group">
<label for="checkboxes[]">checkboxes title</label><br>
`<?php
for ($i=0; $i<$anoigmata->getall()[1]; $i++) {
echo "
<input type='hidden' name='checkboxes[$i]' value='0' />
<input type='checkbox' id='checkboxes[$i]' name='checkboxes[$i]' value='".$anoigmata->getall()[0][$i]->ΕΜΒΑΔΟΝ."' />".$anoigmata->getall()[0][$i]->ΠΕΡΙΓΡΑΦΗ."<br>";}?>`
`</div><button type="submit" class="btn btn-success">Submit</button></form>`
***ΕΜΒΑΔΟΝ and ΠΕΡΙΓΡΑΦΗ are the row names from my table that i'm saving!!!
i hope i helped a little..!