IE和Firefox的鼠标滚轮事件JavaScript代码

[网摘]IE和Firefox的鼠标滚轮事件JavaScript代码 

1.==================================
滚轮IE和Firefox的代码不一样：
IE是mousewheel事件，Firefox是DOMMouseScroll事件
事件属性，IE是event.wheelDelta，Firefox是event.detail
属性的方向值也不一样，IE向上滚 > 0，Firefox向下滚 > 0
//滚轮放大或缩小，基于Prototype 1.6
var scrollfunc = function(event) {
        var direct = 0;
        if (event.wheelDelta) {
                direct = event.wheelDelta > 0 ? 1 : -1;
        } else if (event.detail) {
                direct = event.detail < 0 ? 1 : -1;
        }
        zoom(direct);
};
Event.observe(document, 'mousewheel', scrollfunc);
Event.observe(document, 'DOMMouseScroll', scrollfunc); //firefox 


2.==========================================
代码:

 function wheelEvent(obj, handle){
        this.handle = handle;
        
        // different events between Firefox and IE
        window.addEventListener ? obj.addEventListener("DOMMouseScroll", this.wheel, false) : (obj.onmousewheel = this.wheel);
}