Can't Check Checkbox Value With Php and AJAX - php

Question

I have a form and I use one checkbox. Thanks to the Checkbox, a new field is added and the user fills it.
I ran into a problem with everything going perfectly. The checkbox keeps returning empty, which completely destroys my if else structure.
Checkbox HTML Code:
<input type="checkbox" class="custom-control-input headerElementDrop" id="header_element_drop" name="header_element_drop" onchange="valueChanged()">
AJAX Code:
function headerElementInsert() {
var headerElementAdd = $("#headerElementAdd").serialize();
$.ajax({
type: "POST",
data: headerElementAdd,
url: "actions/header-element-add.php",
success: function (insertSuccess) {
if ($.trim(insertSuccess) == "null") {
//
} else if ($.trim(insertSuccess) == "success") {
//
} else if ($.trim(insertSuccess) == "error") {
//
})
}
}
});
}
header-element-add.php code:
if ($_POST) {
$header_element_name = post('header_element_name');
$header_element_icon = post('header_element_icon');
$header_element_link = post('header_element_link');
$header_element_drop = (isset($_POST["header_element_drop"])) ? 1 : 2 ;
$header_element_drop_class_name = post('header_element_drop_class_name');
$header_element_drop_elements = post('header_element_drop_elements');
if($header_element_drop == 1) {
if(!$header_element_name || !$header_element_drop || !$header_element_drop_class_name || !$header_element_drop_elements) {
echo "null";
}else{
$header_element_drop_class = replace_tr($header_element_drop_class_name);
$header_elements = $db->prepare("INSERT IGNORE INTO header_elements SET header_element_name=?, header_element_icon=?, header_element_link=?, header_element_drop=?, header_element_drop_class_name=?, header_element_drop_class=?, header_element_drop_elements=?");
$insert = $header_elements->execute(array($header_element_name,$header_element_icon,$header_element_link,$header_element_drop,$header_element_drop_class_name,$header_element_drop_class,$header_element_drop_elements));
if($insert) {
echo "success";
}else{
echo "error";
}
}
}else{
if(!$header_element_name) {
echo "null";
}else {
$header_elements = $db->prepare("INSERT IGNORE INTO header_elements SET header_element_name=?, header_element_icon=?, header_element_link=?");
$insert = $header_elements->execute(array($header_element_name,$header_element_icon,$header_element_link));
if($insert) {
echo "success";
}else{
echo "error";
}
}
}
}
I tried many ways to solve this problem but none of them worked. I would really appreciate if you could help.

Answer 1

I found the problem. I forgot to give name value to one input. I apologize for the inconvenience caused.