Adding JS code to make the popup appear when clicking at selected element

Here is the JS code, which would allow you to make the popup apper when you click at selected element, not only on "Add to Cart" button:

<script>
jQuery('body').on('click', '#yourIDbutton', function() {
    jQuery('.festi-cart-pop-up-header').css('display', 'none'); /* Hides the header text */
    jQuery('#festi-cart-pop-up-content').bPopup({
        modalClose: true,
        positionStyle: 'absolute'
    });
    return false;
});
</script>