将值从jquery传递到同一页面中的php变量

I know similar questions to this have been asked before but I don't see an answer that suits my question. I have a div that triggers a jquery script which stores an id. I can get the id into a variable in the jquery but I want to then assign that id to a PHP variable that exists on the same page.

So far this is what I've got. Here is my div that exists in index.php:

echo '<div id="'.$unit_id.'" class="dropdown unit '.$unit_size.' unit-'.$unit_number.' '.$unit_status.' data-unit-id-'.$unit_id.'">';

And here is my jquery that I call in from functions.php:

<script>
    $('.unit.available').click(function(){
        var unit_id = $(this).attr('id');
        $.ajax({
            type: 'post',
            data: {id: unit_id}, //Pass the id
        });
    });
</script>

I want to pass the unit_id into a variable on index.php called $getID but I can't seem to find a way of getting in there. I've tried using post but there really isn't a form being submitted. It's just a dive being clicked on.

You must change your id in your <div> and set it to fetch the variable sent by jQuery. Other than that, your jQuery script looks fine.

Here's how I would do it:

# Fetch the variable if it's set.
<?php $unit_id = (isset($_POST["id"])) ? $_POST["id"] : null; ?>

# Echo it as the id of the div.
<div id = "<?= $unit_id; ?>" class = "dropdown unit"></div>

EDIT:

The PHP code above is equal to:

# Fetch the variable if it's set.
<?php
    if (isset($_POST["id"])):
        $unit_id = $_POST["id"];
    else:
        $unit_id = null;
    endif;
?>

Assign id to div id attribute like this, Use:

<div id="<?php echo $unit_id; ?>" class="dropdown unit"></div>

Try this hope it will work

<div id="<?php echo $unit_id;?>" class="dropdown unit"></div>


<script>
    $('.unit.available').click(function(){
        var unit_id = $(this).attr('id');
        $.ajax({
            type: 'post',
            'id='+unit_id, //Pass the id
        });
    });
</script>

What you mean by this '$unit_id' in div ID. Just put the code in PHP Tag, while working with PHP in HTML pages use the code inside PHP tags.

Availale PHP tags : <?php echo $unit_id ?> (or) <?=$unit_id ?> (short tag).

Change your div with :

<div id="<?=$unit_id ?>" class="dropdown unit"></div>

or

<div id="<?php echo $unit_id ?>" class="dropdown unit"></div>

Then your script will be work

<script>
    $('.unit.available').click(function(){
        var unit_id = $(this).attr('id');
       // to check whether value passing or not 
       console.log(unit_id);
        $.ajax({
            type: 'post',
            data: {id: unit_id}, //Pass the id
        });
    });
</script>