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Revision: 61069
at November 26, 2012 05:14 by zfisic


Updated Code
// creates a global "addWheelListener" method
// example: addWheelListener( elem, callback );

(function(window,document) {
 
    var prefix = "", _addEventListener, onwheel, support;
 
    // detect event model
    if ( window.addEventListener ) {
        _addEventListener = "addEventListener";
    } else {
        _addEventListener = "attachEvent";
        prefix = "on";
    }

    // detect available wheel event
    if ( document.onmousewheel !== undefined ) {
        // Webkit and IE support at least "mousewheel"
        support = "mousewheel"
    }
    try {
        // Modern browsers support "wheel"
        WheelEvent("wheel");
        support = "wheel";
    } catch (e) {}
    if ( !support ) {
        // let's assume that remaining browsers are older Firefox
        support = "DOMMouseScroll";
    }
    window.addWheelListener = function( elem, callback, useCapture ) {
        _addWheelListener( elem, support, callback, useCapture );
 
        // handle MozMousePixelScroll in older Firefox
        if( support == "DOMMouseScroll" ) {
            _addWheelListener( elem, "MozMousePixelScroll", callback, useCapture );
        }
    };
 
    function _addWheelListener( elem, eventName, callback, useCapture ) {
        elem[ _addEventListener ]( prefix + eventName, support == "wheel" ? callback : function( originalEvent ) {
            !originalEvent && ( originalEvent = window.event );
 
            // create a normalized event object
            var event = {
                // keep a ref to the original event object
                originalEvent: originalEvent,
                target: originalEvent.target || originalEvent.srcElement,
                type: "wheel",
                deltaMode: originalEvent.type == "MozMousePixelScroll" ? 0 : 1,
                deltaX: 0,
                delatZ: 0,
                preventDefault: function() {
                    originalEvent.preventDefault ?
                        originalEvent.preventDefault() :
                        originalEvent.returnValue = false;
                }
            };
             
            // calculate deltaY (and deltaX) according to the event
            if ( support == "mousewheel" ) {
                event.deltaY = - 1/40 * originalEvent.wheelDelta;
                // Webkit also support wheelDeltaX
                originalEvent.wheelDeltaX && ( event.deltaX = - 1/40 * originalEvent.wheelDeltaX );
            } else {
                event.deltaY = originalEvent.detail;
            }
 
            // it's time to fire the callback
            return callback( event );
 
        }, useCapture || false );
    }
 
})(window,document);

Revision: 61068
at November 26, 2012 05:10 by zfisic


Initial Code
(function(window,document) {
 
    var prefix = "", _addEventListener, onwheel, support;
 
    // detect event model
    if ( window.addEventListener ) {
        _addEventListener = "addEventListener";
    } else {
        _addEventListener = "attachEvent";
        prefix = "on";
    }

    // detect available wheel event
    if ( document.onmousewheel !== undefined ) {
        // Webkit and IE support at least "mousewheel"
        support = "mousewheel"
    }
    try {
        // Modern browsers support "wheel"
        WheelEvent("wheel");
        support = "wheel";
    } catch (e) {}
    if ( !support ) {
        // let's assume that remaining browsers are older Firefox
        support = "DOMMouseScroll";
    }
    window.addWheelListener = function( elem, callback, useCapture ) {
        _addWheelListener( elem, support, callback, useCapture );
 
        // handle MozMousePixelScroll in older Firefox
        if( support == "DOMMouseScroll" ) {
            _addWheelListener( elem, "MozMousePixelScroll", callback, useCapture );
        }
    };
 
    function _addWheelListener( elem, eventName, callback, useCapture ) {
        elem[ _addEventListener ]( prefix + eventName, support == "wheel" ? callback : function( originalEvent ) {
            !originalEvent && ( originalEvent = window.event );
 
            // create a normalized event object
            var event = {
                // keep a ref to the original event object
                originalEvent: originalEvent,
                target: originalEvent.target || originalEvent.srcElement,
                type: "wheel",
                deltaMode: originalEvent.type == "MozMousePixelScroll" ? 0 : 1,
                deltaX: 0,
                delatZ: 0,
                preventDefault: function() {
                    originalEvent.preventDefault ?
                        originalEvent.preventDefault() :
                        originalEvent.returnValue = false;
                }
            };
             
            // calculate deltaY (and deltaX) according to the event
            if ( support == "mousewheel" ) {
                event.deltaY = - 1/40 * originalEvent.wheelDelta;
                // Webkit also support wheelDeltaX
                originalEvent.wheelDeltaX && ( event.deltaX = - 1/40 * originalEvent.wheelDeltaX );
            } else {
                event.deltaY = originalEvent.detail;
            }
 
            // it's time to fire the callback
            return callback( event );
 
        }, useCapture || false );
    }
 
})(window,document);

Initial URL
https://developer.mozilla.org/en-US/docs/DOM/DOM_event_reference/wheel?redirect=no

Initial Description
A nifty event listener for handling wheel events. Listens for the DOM3 Wheel Event first, then falls back to MouseWheel, and finally DOMMouseScroll.

Initial Title
Cross Browser Wheel Event Listener

Initial Tags

                                

Initial Language
JavaScript