https://themotorcyclebook.com/Resources/fwResponsiveMenus.js

1(function() {
2    var e = document.querySelectorAll("input[id$='-toggle']");
3    for(var i=0;i<e.length;i++){
4       fwAddListener(e[i], "change",function() {
5            var _this = this,
6                container = document.querySelector("#" + _this.id + " ~ [class*='fwNavContainer']"),
7				parent = this.parentNode;
8        	while(!(/PageDiv/.test(parent.id))) {
9        		parent.style.zIndex = "999999";
10        		parent = parent.parentNode;
11        	}
12            fwAddListener(container, "transitionend", function() {
13                if(_this.checked) {
14                    document.querySelector("body").style.overflow = "hidden"
15                }
16                else {
17                	var parent = _this.parentNode;
18                	while(!(/PageDiv/.test(parent.id))) {
19                		parent.style.zIndex = "";
20                		parent = parent.parentNode;
21                	}
22                    document.querySelector("body").style.overflow = "";
23                }
24            });
25       });
26    }
27    e = document.querySelectorAll(".fwNavItem a");
28    for(i=0;i<e.length;i++){
29       fwAddListener(e[i], "click",function() {
30       		if(!(/#/.test(this.href)))
31       			return;
32       		var parent = this.parentNode;
33       		while(!(/fwNavContainer/.test(parent.className))) {
34       			parent = parent.parentNode;
35       			if(!parent)
36       				return;
37       		}
38       		parent.parentNode.querySelector("input[id$='-toggle']").checked = false;
39       		fwToggleMenu(parent.parentNode.parentNode);
40            document.querySelector("html").style.overflow = document.querySelector("body").style.overflow = "";
41       });
42    }
43})();
44function fwToggleMenu(c)
45{
46  var e = c.parentNode.querySelector("[class*='fwNavContainer']");
47  if(c.checked)
48    e.className += " fwMenuOn";
49  else
50    e.className = e.className.replace(" fwMenuOn", "");
51}
52function fwShowHideMenu(id, screenWidth)
53{
54	if(Math.max(document.documentElement.clientWidth, window.innerWidth || 0) <= screenWidth)
55		setTimeout(function() { document.querySelector("#" + id + " [class*='fwNavContainer']").style.display = Math.max(document.documentElement.clientWidth, window.innerWidth || 0) <= screenWidth ? "block" : "" }, 1000);
56	else
57    {
58		document.querySelector("#" + id + " [class*='fwNavContainer']").style.display = "";
59        document.querySelector("html").style.overflow = document.querySelector("body").style.overflow = "";
60    }
61}
62function fwAddListener(element, type, callback)
63{
64    if (element.addEventListener) element.addEventListener(type, callback);
65    else if (element.attachEvent) element.attachEvent('on' + type, callback);
66}�