Fire event after scrollling scrollbars or mousewheel with javascript

This event does not exist. You can emulate it by using timeouts:

Example (concept code):

(function() {
    var timer;
    /* Basic "listener" */
    function scroll_finish(ev) {
        clearTimeout(timer);
        timer = setTimeout(scroll_finished, 200, ev);
        //200ms. Too small = triggered too fast. Too high = reliable, but slow
    }
    window.onscroll = scroll_finish; // Or addEventListener, it's just a demo

    // Fire "events"
    var thingey = [];
    function scroll_finished(ev) {
        // Function logic
        for (var i=0; i<thingey.length; i++) {
            thingey[i](ev);
        }
    }
    // Add listener
    window.addScrollListener = function(fn) {
        if (typeof fn  === 'function') {
            thingey.push(fn);
        } else {
           throw TypeError('addScrollListener: First argument must be a function.');
        }
    }
    window.removeScrollListener = function(fn) {
        var index = thingey.indexOf(fn);
        if (index !== -1) thingey.splice(index, 1);
    }
})();