JS - window ready event in pure Javascript, iterate NodeList

JS_window_event_iterate_nodelist.js

(function () {

    // Window ready event in pure JS
    window.addEventListener('load', ready, false);

    function ready () {   
        changeNum(7);
    }

    function changeNum (num = 1) {
        var n = document.querySelectorAll('.number');

        // Iterate NodeList
        [].forEach.call(n, function (el) {
            el.innerHTML = num;
        });
    }
})(window);