html - 可滚动的 div : how to detect scroll direction from OnScroll event for a scrollable div?

Question

如何从 OnScroll 事件检测可滚动 div 的滚动方向？如果用户向上滚动，我想将 15 添加到 scrollTop，如果用户向下滚动，则减去 15。不使用 JQuery 是否可行？

Answer 1

JSFIDDLE

/**
 * Calculate incremental amounts of pixels scrolled in each axis.
 * Value is signed to its direction.
 */
function incrementalScroll(e) {

    var scrollX = (this.x || window.pageXOffset) - window.pageXOffset;
    var scrollY = (this.y || window.pageYOffset) - window.pageYOffset;

    this.x = window.pageXOffset;
    this.y = window.pageYOffset;

    test(scrollX, scrollY);
}

window.onscroll = incrementalScroll;

随心所欲地使用它。

function test(scrollX, scrollY){

    var directionX = !scrollX ? "NONE" : scrollX>0 ? "LEFT" : "RIGHT";
    var directionY = !scrollY ? "NONE" : scrollY>0 ? "UP" : "DOWN";

    console.log(directionX, scrollX, directionY, scrollY);
}