判断滚轮滚动方向

 <p><label for="wheelDelta">  滚动值:</label>(IE/Opera)<input type="text" id="wheelDelta" /></p>
 <p><label for="detail"> 滚动值:(Firefox)</label><input type="text" id="detail" /></p>
 <script type="text/javascript">
     var oTxt = document.getElementById("txt");
     /***********************
     * 函数：判断滚轮滚动方向
     * 返回：滚轮方向 1：向上 -1：向下
     *************************/
     var scrollFunc = function (e) {
         var direct = 0;
         e = e || window.event;

         var t1 = document.getElementById("wheelDelta");
         var t2 = document.getElementById("detail");
         if (e.wheelDelta) {//IE/Opera/Chrome
             t1.value = e.wheelDelta;
         } else if (e.detail) {//Firefox
             t2.value = e.detail;
         }
         ScrollText(direct);
     }
     /*注册事件*/
     if (document.addEventListener) {
         document.addEventListener('DOMMouseScroll', scrollFunc, false);
     } //W3C
     window.onmousewheel = document.onmousewheel = scrollFunc; //IE/Opera/Chrome/Safari
</script>