无需使用pageYOffset即可检测车轮方向的Javascript(或其他lang)

问题描述

我的页面不高于窗口=>它没有滚动器.

I have a page not higher than the window => it has no scroller.

如何检测车轮滚动的方向?

How can I detect the direction, in which the wheel is rolled?

如果JavaScript无法解决这个问题，那么还有其他网络语言可以帮助我解决这个问题吗?

And if JavaScript can't handle this, is there some other net language to help my case?

谢谢

推荐答案

在车轮"事件的MDN页面，转载如下:

(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
    support = "onwheel" in document.createElement("div") ? "wheel" : // Modern browsers support "wheel"
              document.onmousewheel !== undefined ? "mousewheel" : // Webkit and IE support at least "mousewheel"
              "DOMMouseScroll"; // let's assume that remaining browsers are older Firefox

    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,
                deltaZ: 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);

然后您可以:

addWheelListener( document, function( e ) {
    console.log( e.deltaY < 0 ? "up" : "down" );
    e.preventDefault();
} );

这篇关于无需使用pageYOffset即可检测车轮方向的Javascript(或其他lang)的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！