How to get element by parent classname in PHP - php

Question

HTML markup:
<form>
<div class="required">
<input id="name" name="name">
</div>
<div class="required">
<input id="email" name="email">
</div>
<div class="non-required">
<input id="other" name="other">
</div>
...
alot of input here
...
</form>
PHP:
<?php
extract($_POST, EXTR_PREFIX_ALL, 'input');
if (empty($input_name) || empty($input_email) || empty($input_other) || ... alot of input here...) { // i want only the input that has `required` class in this line
// main function here
}
?>
I can manually edit it but how can auto select input that has required class for the PHP main function?
Thanks.

Answer 1

You can't access the parent's class name. This information is not transmitted when the user submits the form.
The only information available in $_POST are the name and value of the input element. You could define the names of your input elements to represent required / non required like that:
<form>
<div class="required">
<input id="name" name="required[name]">
</div>
<div class="required">
<input id="email" name="required[email]">
</div>
<div class="optional">
<input id="another" name="optional[another]">
</div>
<div class="required">
<input id="other" name="required[other]">
</div>
</form>
Using this schema you will have two sub arrays in $_POST, named required and optional:
Array //$_POST
(
[required] => Array
(
[name] => value,
[email] => value,
[name] => value
),
[optional] => Array
(
[another] => value
)
)
Warning
If you're using this solution please make sure you're validating the input correctly. You are going to trust the user agent to provide correct information about the fields. Look at Trincot's answer for a purely server side solution.

Answer 2

Since you produce the HTML yourself, you actually know which input elements have the class "required". So I would propose you first create an array with the required fields, and generate the HTML from that with dynamically class values.
Then later you can use the same array to check for emptiness:
HTML generation:
<?php
// define the list of required inputs:
$required = array("name", "email");
// define a function that returns "required" or "non-required"
// based on the above array.
function req($name) {
global $required;
return in_array($required, $name) ? 'required' : 'non-required';
}
// Now generate the classes dynamically, based on the above:
?>
<form>
<div class="<?=req('name')?>">
<input id="name" name="name">
</div>
<div class="<?=req('email')?>">
<input id="email" name="email">
</div>
<div class="<?=req('other')?>">
<input id="other" name="other">
</div>
...
alot of input here
...
</form>
Then in the processing of the input, use the above function again:
<?php
// This extract is not needed for the next loop, but you might need it still:
extract($_POST, EXTR_PREFIX_ALL, 'input');
// go through all inputs that are required and test for empty
// until you find one, and produce the appropriate response
foreach($required as $name) {
if (empty($_POST[$name])) {
// main (error?) function here
break; // no need to continue the loop as we already found an empty one
}
}
?>