鼠标滑轮滚动事件

var wheel = function(event) {  
            var delta = 0;
            console.log(event);  
            if (!event) /* For IE. */  
                event = window.event;  
            if (event.wheelDelta) { /* IE/Opera/Chrome. 鼠标向上滑 120*/  
                delta = event.wheelDelta / 120;  
            } else if (event.detail) {  
                /** Mozilla case. */  
                /** In Mozilla, sign of delta is different than in IE. 
                 * Also, delta is multiple of 3. 鼠标向上滑为 -3 为了统一正负号（方向） 
                 */  
                delta = -event.detail / 3;  
            }  
            /** If delta is nonzero, handle it. 
             * Basically, delta is now positive if wheel was scrolled up, 
             * and negative, if wheel was scrolled down. 
             */  
            if (delta)  
                handle(delta);  
            /** Prevent default actions caused by mouse wheel. 
             * That might be ugly, but we handle scrolls somehow 
             * anyway, so don't bother here.. 
             */  
            if (event.preventDefault)  
                event.preventDefault();  
            event.returnValue = false;  
        }  
  
        /** Initialization code.  
         * If you use your own event management code, change it as required. 
         */  
        if (window.addEventListener) {  
            /** DOMMouseScroll is for mozilla. */  
            window.addEventListener('DOMMouseScroll', wheel, false);  
        }  
        /** IE/Opera. */  
        window.onmousewheel = document.onmousewheel = wheel;  
  
        /** This is high-level function. 
         * It must react to delta being more/less than zero. 
         */  
        var handle = function(delta) {  
            
            if (delta < 0) {  
                 alert("鼠标滑轮向下滚动：" + delta + "次！"); // 1  
                return;  
            } else {  
                alert("鼠标滑轮向上滚动：" + delta + "次！"); // -1                 
                return;  
            }  
        }

function mousewheel(ev){
    var oEvent=ev||event;
    var dir=true;
    if(oEvent.wheelDelta){
         console.log("wheelDelta："+oEvent.wheelDelta);
          dir=oEvent.wheelDelta>0?true:false;
          //向上滚动为120
         //向下滚动为-120    
    }else{
        //火狐的event.detail向下滑为正数，值与其他浏览器相反
        console.log("detail："+oEvent.wheelDelta);
         dir=oEvent.detail<0?true:false;
         //向上滚动为-3
        //向下滚动为3
    }
    //根据手表方向设定具体业务逻辑
    if(dir){
      oBox.style.height=oBox.offsetHeight-10+'px';    
    }else{
      oBox.style.height=oBox.offsetHeight+10+'px';
    }
    // addEventLisrener 绑定的时间需要通过event对象下面的的 preventDefaul
    if(oEvent.preventDefault){
      oEvent.preventDefault();
    }
    return false;//阻止默认行为(阻止的是 obj.on时间名称=fn 所触发的默认行为)
    
}

//添加事件 ie chrome
  document.onmousewheel=mousewheel;
  if(document.addEventListener){
    //火狐 chrome
    document.addEventListener('DOMMouseScroll',mousewheel,false);
  }