Mouse wheel listener for JavaScript.

mouse-wheel-listener.js

'use strict';

(function(window) {
    
    //
    // Manipulate Mouse Wheel
    // source: http://www.adomas.org/javascript-mouse-wheel/index.html
    //
    /**
     * Function: MouseWheelEvent
     * 
     * Manipulate mouse wheel actions.
     *
     * Parameters:
     *     (Integer) delta - A value that determines the directions of the scrolling.
     *
     * Returns:
     *     null
     *
     * See Also:
     *     <MouseWheel>
     */
    function MouseWheelEvent(delta) {
        if (delta < 0) { // scroll down
        } else { // scroll up
        }
    }

    /**
     * Function: MouseWheelEvent
     * 
     * Listen for the mouse wheel movements and triggers a function.
     *
     * Parameters:
     *     (Object) event - Event passed by mouse scroll.
     *
     * Returns:
     *     null
     *
     * See Also:
     *     <MouseWheelEvent>
     */
    function MouseWheel(event) {
        var delta = 0;
        if (!event) {
            event = window.event;
        }
        if (event.wheelDelta) {
            delta = event.wheelDelta / 120;
        } else if (event.detail) {
            delta = -event.detail / 3;
        }
        if (delta) {
            new MouseWheelEvent(delta);
        }
        if (event.preventDefault) {
            event.preventDefault();
        }
        event.returnValue = false;
    }

    /* Mouse wheel listener. */
    if (window.addEventListener) {
        window.addEventListener('DOMMouseScroll', MouseWheel, false);
    }
    window.onmousewheel = MouseWheel;

})(window);