<body>
<div class="wrap">
<div class="scroll"></div>
</div>
</body>
<script type="text/javascript">
var scrollTop = 0;
var t = 0;
var wrapdom=document.querySelector('.wrap');
wrapdom.onscroll=function () {
scrollTop =wrapdom.scrollTop; //滚动高度
if (t <= scrollTop) {
console.log("往下滚动");
} else {
console.log("往上滚动");
}
t = scrollTop;
};
</script>