Why is JS curtain not working?

Question

css

The best answer was given by Vitaly!
hammerk^_^

$(".mc_item_wrap").click(function(){
 
            $(this).children("ul").slideToggle();
});

Answer 1

in general, all your uls fall into the selection,
try to go to the parent once
$(this).parent("li").children("ul")

Answer 2

the selector $(this).parent().parent().children("ul") returns an empty array. Maybe this will push you.

Answer 3

Now everyone sees Vitaly's answer and wonders what kind of curtain ...