How to pass post id to modal window in php code?

Question

JavaScript

Kind.

When you click on a post, a modal window opens.

Code in modal window.

<?php 
$id = 70;
echo do_shortcode( ''.get_field('slider_exercises', $id).'' ); 
?>

The code displays the gallery from the post via the ACF plugin. If you do not specify the $id of the post, then the gallery will not be displayed.
JS when clicking on a post takes the id of the post and places it in any specified attribute of the modal window.
How can I put this id into the $id variable of the php code, or how can I extract the id number from the html attribute with php code.
Or maybe there is another way?

Thank you!

Answer 1

i.e. you manually specify the $id to display some post now?