multi-select-add-class.php

<script>
jQuery(document).ready(function($) {
    "use strict";
    $("#field_1f2ra-0, #field_vufrc-0, #field_kpv4b-0, #field_kpv4b-1, #field_kpv4b-2, #field_4tih-0, #field_kv3rj-1, ").on(change, function() {
        if ( $(this).prop("checked") ) {
            $(this).addClass("stay-black");
        } else {
            $(this).removeClass("stay-black");
        }
    });
});
</script>