<script>
   var scrollFunc = function (e) {
    var direct = 0;
    e = e || window.event;
    if (e.wheelDelta) {  //判斷瀏覽器IE，谷歌滑輪事件             
        if (e.wheelDelta > 0) { //當滑輪向上滾動時
            alert("滑輪向上滾動");
        }
        if (e.wheelDelta < 0) { //當滑輪向下滾動時
            alert("滑輪向下滾動");
        }
    } else if (e.detail) {  //Firefox滑輪事件
        if (e.detail> 0) { //當滑輪向上滾動時
            alert("滑輪向上滾動");
        }
        if (e.detail< 0) { //當滑輪向下滾動時
            alert("滑輪向下滾動");
        }
    }
    ScrollText(direct);
}
    //給頁面繫結滑輪滾動事件
    if (document.addEventListener) {
        document.addEventListener('DOMMouseScroll', scrollFunc, false);
    }
    //滾動滑輪觸發scrollFunc方法
    window.onmousewheel = document.onmousewheel = scrollFunc;  
</script>