How to get submitted variable into a function - php

Question

I am very sorry if this is very obvious, but I am banging my head against the wall on how to solve this
I have a form and I would like to use the submitted form value in to a function
the form:
form.php
<form action="my.php" method="post" enctype="multipart/form-data">
<input id="my-item-calc" name="my-item-calc" value="29.00">
<td>
<input type="submit">
</form>
my.php
class Jcart{
private $calcdel =0;
public function get_contents() {
return $items;
return $calc['calcdel'];
}
private function add_calc($calcdel){
$validCalcdel = false;
//Verify if the calculate value is numberic
if (is_numeric($calcdel)) {
$validCalcdel = true;
}
if ($validCaldel !== false) {
$this->calcdel = $calcdel;
}
}
public function display_cart() {
$config = $this->config;
$errorMessage = null;
// Simplify some config variables
$checkout = $config['checkoutPath'];
$priceFormat = $config['priceFormat'];
$calcdel = $config['calc']['calcdel'];
// Use config values as literal indices for incoming POST values
// Values are the HTML name attributes set in config.json
$calcdel= $_POST[$calcdel];
if ( isset($_POST[$calcdel]) ) {
$calcdel = $_POST[$calcdel];
$calcAdded = $this->add_calc($calcdel);
if ($calcAdded = true){
$this->calcdel = $calcdel;
}
}
}
}
When I submit the form it will echo 29.00 for the $calcdel how ever this $this->calcdel output is empty
Any help how I would be able to pass the value into $this->calcdel and echo it out

Answer 1

Hope this will work
class Jcart{
private $calcdel =0;
public function get_contents() {
return $items;
return $calc['calcdel'];
}
private function add_calc($calcdel){
$validCalcdel = false;
//Verify if the calculate value is numberic
if (is_numeric($calcdel)){
$validCalcdel = true;}
if ($validCaldel !== false){
$this->calcdel = $calcdel;
}
}
public function display_cart() {
$config = $this->config;
$errorMessage = null;
// Simplify some config variables
$checkout = $config['checkoutPath'];
$priceFormat = $config['priceFormat'];
$calcdel = $config['calc']['calcdel'];
// Use config values as literal indices for incoming POST values
// Values are the HTML name attributes set in config.json
$calcdel= $_POST[$calcdel];
$calcAdded = $this->add_calc($calcdel);
if ($calcAdded){
$this->calcdel = $calcdel;
}
}}
$jcart = new Jcart();
if (isset($_POST[$calcdel]))
{
$jcart->display_cart();
}