JS实现利用闭包判断Dom元素和滚动条的方向示例

function scroll(fn) {
    //利用闭包判断滚动条滚动的方向
    var beforeScrollTop = document.body.scrollTop,
      fn = fn || function() {};
    window.addEventListener("scroll", function() {
      var afterScrollTop = document.body.scrollTop,
        delta = afterScrollTop - beforeScrollTop;
      if (delta === 0) return false;
      fn(delta > 0 "down" : "up");
      beforeScrollTop = afterScrollTop;
    }, false);
}
scroll(function(direction) { console.log(direction) });

function direction() {
    var lastX = null,
      lastY = null;
    window.addEventListener("mousemove", function(event) {
      var curX = event.clientX,
        curY = event.clientY,
        direction = '';
      // console.info(event);
      // console.info(event.clientX);
      // console.info(event.clientY);
      // 初始化坐标
      if (lastX == null || lastY == null) {
        lastX = curX;
        lastY = curY;
        return;
      }
      if (curX > lastX) {
        direction += 'X右,';
      } else if (curX < lastX) {
        direction += 'X左,';
      }
      if (curY > lastY) {
        direction += 'Y下';
      } else if (curY < lastY) {
        direction += 'Y上';
      }
      lastX = curX;
      lastY = curY;
      //console.info(direction);
      document.getElementById("test").innerText = direction;
    })
}

var gaga = function(wrap) {
    var wrap = document.getElementById(wrap);
    var hoverDir = function(e) {
      var w = wrap.offsetWidth,
        h = wrap.offsetHeight,
        x = (e.clientX - wrap.offsetLeft - (w / 2)) * (w > h "_blank" href="//www.jb51.net/Special/85.htm">javascript面向对象入门教程》、《JavaScript错误与调试技巧总结》、《JavaScript数据结构与算法技巧总结》、《JavaScript遍历算法与技巧总结》及《JavaScript数学运算用法总结》

希望本文所述对大家JavaScript程序设计有所帮助。