鼠标滑轮

Question

当触发鼠标滑轮事件的时候怎么判断是向上 还是向下?????

Answer 1

FF DOMMouseScroll事件　detail 有正负
ie onmousewheel事件　wheelDelta 

Answer 2

 <script type="text/javascript">
    var distance=0;
    var now=0;
    window.onscroll = function() {
        now = document.documentElement.scrollTop;
        if (now > distance) {
            document.getElementById("Text1").value = "Down";
        }
        if (now < distance) {
            document.getElementById("Text1").value="Up";
        }
        distance = now;
    }
    </script>