slicknav not working on iphone 6 safari

Question

I have slicknav working on a desktop in chrome, ie, safari and firefox. When I run on the iphone 6 it works in chrome but not in safari. my js function looks like:

$(document).ready(function() {
   $("#nav_lat").slicknav({prependTo:"#mobile_menu"});
});

the safari console from iphone 6 says:

$("#nav_lat").slicknav({prependTo:"#mobile_menu"});

is not a function. Have no idea how to fix this. help appreciated.

here's a link to the website:

halloween

if you reduce the screen size you'll see the slicknav plugin working on a desktop. But unless you use chrome it doesn't work on the iphone 6

Did some more testing and the plugin works fine on the iphone 6S but still not working on the Iphone 6

Answer 1

If I use:

$(document).ready(function() {
  $("#nav_lat").slicknav({prependTo:"#mobile_menu"});
 });

It doesn’t work on the iphone 6 but it does seem to work everywhere else

However, if I use

jQuery(function($) {
   $("#nav_lat").slicknav({prependTo:"#mobile_menu"});
 });

It seems to work every where Could someone explain what's going on?