js 實時監聽滾動條狀態 判斷滾動條位置

  var scrollFunc = function (e) { 
             
           e = e || window.event; 
        
            var t = document.documentElement.scrollTop || document.body.scrollTop; //變量t就是滾動條滾動
             if (t <=100) {
                $(".top-header").attr('style','background:transport');
               
            }else{
                $(".top-header").attr('style','background:#47467e');
            } 
            
               
        /*     console.log(t); */
          /*  if (e.wheelDelta) { //第一步：先判斷瀏覽器IE，谷歌滑輪事件    
            if (e.wheelDelta > 0) { //當滑輪向上滾動時 
             console.log("滑輪向上滾動"); 
            } 
            if (e.wheelDelta < 0) { //當滑輪向下滾動時 
             console.log("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 
             console.log("滑輪向上滾動"); 
            } 
            if (e.detail< 0) { //當滑輪向下滾動時 
             console.log("滑輪向下滾動"); 
            } 
           } */
          }
          

        //給頁面綁定滑輪滾動事件 
        if (document.addEventListener) { //firefox 
            document.addEventListener('DOMMouseScroll', scrollFunc, false);
        }
        //滾動滑輪觸發scrollFunc方法 //ie 谷歌 
        window.onmousewheel = document.onmousewheel = scrollFunc;