js判断鼠标滑轮滚动方向并根据滚动的方向触发不同的事件

<script>

   var scrollFunc = function (e) {

        var direct = 0;

        e = e || window.event;

        if (e.wheelDelta) {  //判断浏览器IE，谷歌滑轮事件             

            if (e.wheelDelta > 0) { //当滑轮向上滚动时

                alert("滑轮向上滚动");

            }

            if (e.wheelDelta < 0) { //当滑轮向下滚动时

                alert("滑轮向下滚动");

            }

        } else if (e.detail) {  //Firefox滑轮事件

            if (e.detail> 0) { //当滑轮向上滚动时

                alert("滑轮向上滚动");

            }

            if (e.detail< 0) { //当滑轮向下滚动时

                alert("滑轮向下滚动");

            }

        }

        ScrollText(direct);

    }

    //给页面绑定滑轮滚动事件

    if (document.addEventListener) {

        document.addEventListener('DOMMouseScroll', scrollFunc, false);

    }

    //滚动滑轮触发scrollFunc方法

    window.onmousewheel = document.onmousewheel = scrollFunc;  

</script>