controlling jquery with php problem with current page item

This problem is really driving me insane,.

I’m not sure anymore if this is even possible.
Here’s the problem:

I have this Fancy Jquery for my navigation on this website i’m building:
https://dragendekracht.nl/test/

What i’m trying to accomplish is when clicked on (for example) “mediation” a submenu appears, when clicked on an item in the submenu i want the little gray arrow to remain on it’s parent page (the current position).

It might be extremly easy for some of you,. but for me this is really something i don’t know how to solve. I’ve been searching google for days.

here’s the jquery script:

$(function(){

    var $el, leftPos, newWidth,
        $mainNav = $("#navbar_tabmenu");

    $mainNav.append("<li id='magic-line'></li>");

    var $magicLine = $("#magic-line");

    $magicLine
        .width($(".current_page_item").width())
        .css("left", $(".current_page_item a").position().left)
        .data("origLeft", $magicLine.position().left)
        .data("origWidth", $magicLine.width());

    $("#navbar_tabmenu li").find("a").hover(function() {
        $el = $(this);
        leftPos = $el.position().left;
        newWidth = $el.parent().width();

        $magicLine.stop().animate({
            left: leftPos,
            width: newWidth
        });
    }, function() {
        $magicLine.stop().animate({
            left: $magicLine.data("origLeft"),
            width: $magicLine.data("origWidth")
        });
    });
});

So how do i use the PHP (or something else for that matter) to make clear to the Jquery script to stop moving the arrow (arrow = magicLine see script) if clicked on a subpage?

For anyone who can solve this,.. i’m eternaly gratefull!