IE supports forEach(...) when invoked fromthe console but not when called from the code

Basically document.querySelectorAll would return a nodeList an array like object not an array. You have to convert it to an array before invoking array functions over that.

var menus = document.querySelectorAll("ul.application>li>a");
menus = [].slice.call(menus);
menus.forEach(function(element) { ... });

If your environment supports ES6 then you can use Array.from()

var menus = document.querySelectorAll("ul.application>li>a");
menus = Array.from(menus);
menus.forEach(function(element) { ... });

It is not a problem of the browser, it is more like you get an array like object, with querySelectorAll. It returns a NodeList, which is iterable, but not directly with array methods.

But you can borrow the method from Array.prototype, like this one

Array.prototype.forEach.call(menu, function(element) { /* ... */ });

If you like to get first a real array, you could convert it with

array = Array.apply(null, menu);

Little late, but it might be useful if someone has the same problem and doesn't want/can't replace all forEach methods with [].forEach.call(elements, fn(el)). Here is polyfill that works for ie11

if (! Object.getOwnPropertyDescriptor(NodeList.prototype, 'forEach')) {
    Object.defineProperty(NodeList.prototype, 'forEach', Object.getOwnPropertyDescriptor(Array.prototype, 'forEach'));
}