Set session variable without reloading the page - php

Question

I send a value to a php file with AJAX.
I am having this function in jQuery:
// Service select change
$container.on('change', '.bookly-js-select-service', function() {
var gekozen_behandeling = this.value;
$.ajax({
type: 'POST',
url: '/behandeling.php',
data: {
behandeling_nieuw: gekozen_behandeling
},
dataType: 'html',
success: function(response) {
console.log(response);
}
});
});
After doing this it alerts done.
In my file behandeling.php the code is like this:
<?php
session_start();
$_SESSION["type_behandeling"] = $_POST["behandeling_nieuw"];
echo '<pre>' . print_r($_SESSION, TRUE) . '</pre>';
?>
After doing this and navigate to the behandeling.php file the session variable is still empty.
<pre>Array
(
[bookly] => Array
(
[forms] => Array
(
[5e1c6d8916b27] => Array
(
[defaults] => Array
(
[service_id] => 0
[staff_id] => 0
[location_id] => 0
[category_id] => 5
)
[last_touched] => 1578921357
[data] => Array
(
[first_rendered_step] => 1
[time_zone] =>
[time_zone_offset] =>
[date_from] => 2020-01-13
[days] =>
[time_from] => 09:00
[time_to] => 21:00
[slots] => Array
(
)
[facebook_id] =>
[full_name] =>
[first_name] =>
[last_name] =>
[email] =>
[email_confirm] =>
[phone] =>
[birthday] =>
[additional_address] =>
[country] =>
[state] =>
[postcode] =>
[city] =>
[street] =>
[street_number] =>
[address_iso] => Array
(
)
[notes] =>
[info_fields] => Array
(
)
[coupon_code] =>
[deposit_full] => 0
[edit_cart_keys] => Array
(
)
[repeated] => 0
[repeat_data] => Array
(
)
)
[cart] => Array
(
)
[chain] => Array
(
[0] => Array
(
[service_id] =>
[staff_ids] => Array
(
)
[number_of_persons] =>
[quantity] =>
[extras] => Array
(
)
[custom_fields] => Array
(
)
[location_id] =>
[series_unique_id] => 0
[first_in_series] =>
[units] => 1
)
)
[booking_numbers] => Array
(
)
[payment_id] =>
[payment_type] => local
)
[5e1c6dc0324c7] => Array
(
[defaults] => Array
(
[service_id] => 0
[staff_id] => 0
[location_id] => 0
[category_id] => 5
)
[last_touched] => 1578921411
[data] => Array
(
[first_rendered_step] => 1
[time_zone] =>
[time_zone_offset] =>
[date_from] => 2020-01-13
[days] =>
[time_from] => 09:00
[time_to] => 21:00
[slots] => Array
(
)
[facebook_id] =>
[full_name] =>
[first_name] =>
[last_name] =>
[email] =>
[email_confirm] =>
[phone] =>
[birthday] =>
[additional_address] =>
[country] =>
[state] =>
[postcode] =>
[city] =>
[street] =>
[street_number] =>
[address_iso] => Array
(
)
[notes] =>
[info_fields] => Array
(
)
[coupon_code] =>
[deposit_full] => 0
[edit_cart_keys] => Array
(
)
[repeated] => 0
[repeat_data] => Array
(
)
)
[cart] => Array
(
)
[chain] => Array
(
[0] => Array
(
[service_id] =>
[staff_ids] => Array
(
)
[number_of_persons] =>
[quantity] =>
[extras] => Array
(
)
[custom_fields] => Array
(
)
[location_id] =>
[series_unique_id] => 0
[first_in_series] =>
[units] => 1
)
)
[booking_numbers] => Array
(
)
[payment_id] =>
[payment_type] => local
)
[5e1c6df9da30f] => Array
(
[defaults] => Array
(
[service_id] => 0
[staff_id] => 0
[location_id] => 0
[category_id] => 5
)
[last_touched] => 1578921468
[data] => Array
(
[first_rendered_step] => 1
[time_zone] =>
[time_zone_offset] =>
[date_from] => 2020-01-13
[days] =>
[time_from] => 09:00
[time_to] => 21:00
[slots] => Array
(
)
[facebook_id] =>
[full_name] =>
[first_name] =>
[last_name] =>
[email] =>
[email_confirm] =>
[phone] =>
[birthday] =>
[additional_address] =>
[country] =>
[state] =>
[postcode] =>
[city] =>
[street] =>
[street_number] =>
[address_iso] => Array
(
)
[notes] =>
[info_fields] => Array
(
)
[coupon_code] =>
[deposit_full] => 0
[edit_cart_keys] => Array
(
)
[repeated] => 0
[repeat_data] => Array
(
)
)
[cart] => Array
(
)
[chain] => Array
(
[0] => Array
(
[service_id] =>
[staff_ids] => Array
(
)
[number_of_persons] =>
[quantity] =>
[extras] => Array
(
)
[custom_fields] => Array
(
)
[location_id] =>
[series_unique_id] => 0
[first_in_series] =>
[units] => 1
)
)
[booking_numbers] => Array
(
)
[payment_id] =>
[payment_type] => local
)
[5e1c6e0f76ddd] => Array
(
[defaults] => Array
(
[service_id] => 0
[staff_id] => 0
[location_id] => 0
[category_id] => 5
)
[last_touched] => 1578921490
[data] => Array
(
[first_rendered_step] => 1
[time_zone] =>
[time_zone_offset] =>
[date_from] => 2020-01-13
[days] =>
[time_from] => 09:00
[time_to] => 21:00
[slots] => Array
(
)
[facebook_id] =>
[full_name] =>
[first_name] =>
[last_name] =>
[email] =>
[email_confirm] =>
[phone] =>
[birthday] =>
[additional_address] =>
[country] =>
[state] =>
[postcode] =>
[city] =>
[street] =>
[street_number] =>
[address_iso] => Array
(
)
[notes] =>
[info_fields] => Array
(
)
[coupon_code] =>
[deposit_full] => 0
[edit_cart_keys] => Array
(
)
[repeated] => 0
[repeat_data] => Array
(
)
)
[cart] => Array
(
)
[chain] => Array
(
[0] => Array
(
[service_id] =>
[staff_ids] => Array
(
)
[number_of_persons] =>
[quantity] =>
[extras] => Array
(
)
[custom_fields] => Array
(
)
[location_id] =>
[series_unique_id] => 0
[first_in_series] =>
[units] => 1
)
)
[booking_numbers] => Array
(
)
[payment_id] =>
[payment_type] => local
)
)
)
[type_behandeling] => 51
)
</pre>

Answer 1

It might be possible that when you navigate to behandeling.php
that you are assigning the posted variable to session as
$_SESSION["type_behandeling"] = $_POST["behandeling_nieuw"];
the posted data not found as you are visiting (http get method). Hence session is overwritten with null or empty.

Answer 2

Change dataType: 'html' to dataType: 'JSON'
Through Chrome/Firefox Dev tools check - behandeling.php file is getting called
Through Chrome/Firefox Dev tools check - form data is getting submitted to PHP File
Also if you access the file outside, it Recheck the $_POST Value , since the value is not set, a blank will be assigned to the session.
Check the $_POST Value
if (isset($_POST["behandeling_nieuw"])) {
$_SESSION["type_behandeling"] = $_POST["behandeling_nieuw"];
echo '<pre>' . print_r($_SESSION, TRUE) . '</pre>';
} else {
echo "POST Value not set";
if(isset($_SESSION['type_behandeling']) && !empty($_SESSION['type_behandeling'])) {
echo 'Set and not empty, and no undefined index error!';
}
else {
echo "Session is not set ";
}
}