Hamburger Navigation Menu

You could solve this with other nasty hacks but here’s kind of WordPress way:

In your header.php

<?php
// User is not using mobile
if( ! wp_is_mobile() ) {

    wp_nav_menu(); // Your "original menu"    
}
// User is using mobile
else if( wp_is_mobile() ) {

    wp_nav_menu(); // Your another menu that only has top level items
}
?>

Keep in mind that wp_is_mobile() also considers tablets as mobile devices and you should always carefully think this through because if PC window is resized to small / narrow -> it obviously doesn’t count it as mobile.

And jQuery to disable your click event:

var isMobile = false;

// Check if user is using mobile device
if (/Android|webOS|iPhone|iPad|iPod|BlackBerry|IEMobile|Opera Mini/i.test(navigator.userAgent)) {

    isMobile = true;
}

if( ! isMobile ) {

    // Your usual click event
}