/**
 * Returns Element placement information in Viewport
 * @link https://stackoverflow.com/a/70476497/2453148
 *
 * @typedef {object} ViewportInfo - Whether the element is…
 * @property {boolean} isInViewport - fully or partially in the viewport
 * @property {boolean} isPartiallyInViewport - partially in the viewport
 * @property {boolean} isInsideViewport - fully inside viewport
 * @property {boolean} isAroundViewport - completely covers the viewport
 * @property {boolean} isOnEdge - intersects the edge of viewport
 * @property {boolean} isOnTopEdge - intersects the top edge
 * @property {boolean} isOnRightEdge - intersects the right edge
 * @property {boolean} isOnBottomEdge - is intersects the bottom edge
 * @property {boolean} isOnLeftEdge - is intersects the left edge
 *
 * @param el Element
 * @return {Object} ViewportInfo
 */
function getElementViewportInfo(el) {

    let result = {};

    let rect = el.getBoundingClientRect();
    let windowHeight = window.innerHeight || document.documentElement.clientHeight;
    let windowWidth  = window.innerWidth || document.documentElement.clientWidth;

    let insideX = rect.left >= 0 && rect.left + rect.width <= windowWidth;
    let insideY = rect.top >= 0 && rect.top + rect.height <= windowHeight;

    result.isInsideViewport = insideX && insideY;

    let aroundX = rect.left < 0 && rect.left + rect.width > windowWidth;
    let aroundY = rect.top < 0 && rect.top + rect.height > windowHeight;

    result.isAroundViewport = aroundX && aroundY;

    let onTop    = rect.top < 0 && rect.top + rect.height > 0;
    let onRight  = rect.left < windowWidth && rect.left + rect.width > windowWidth;
    let onLeft   = rect.left < 0 && rect.left + rect.width > 0;
    let onBottom = rect.top < windowHeight && rect.top + rect.height > windowHeight;

    let onY = insideY || aroundY || onTop || onBottom;
    let onX = insideX || aroundX || onLeft || onRight;

    result.isOnTopEdge    = onTop && onX;
    result.isOnRightEdge  = onRight && onY;
    result.isOnBottomEdge = onBottom && onX;
    result.isOnLeftEdge   = onLeft && onY;

    result.isOnEdge = result.isOnLeftEdge || result.isOnRightEdge ||
        result.isOnTopEdge || result.isOnBottomEdge;

    let isInX =
        insideX || aroundX || result.isOnLeftEdge || result.isOnRightEdge;
    let isInY =
        insideY || aroundY || result.isOnTopEdge || result.isOnBottomEdge;

    result.isInViewport = isInX && isInY;

    result.isPartiallyInViewport =
        result.isInViewport && result.isOnEdge;

    return result;
}

对于类似的挑战，我非常喜欢这个要点，它为scrollIntoViewIfNeeded()暴露了一个填充。

所有必要的功夫都需要回答这个问题:

var parent = this.parentNode,
    parentComputedStyle = window.getComputedStyle(parent, null),
    parentBorderTopWidth = parseInt(parentComputedStyle.getPropertyValue('border-top-width')),
    parentBorderLeftWidth = parseInt(parentComputedStyle.getPropertyValue('border-left-width')),
    overTop = this.offsetTop - parent.offsetTop < parent.scrollTop,
    overBottom = (this.offsetTop - parent.offsetTop + this.clientHeight - parentBorderTopWidth) > (parent.scrollTop + parent.clientHeight),
    overLeft = this.offsetLeft - parent.offsetLeft < parent.scrollLeft,
    overRight = (this.offsetLeft - parent.offsetLeft + this.clientWidth - parentBorderLeftWidth) > (parent.scrollLeft + parent.clientWidth),
    alignWithTop = overTop && !overBottom;

这指的是你想知道的元素，例如，overTop或overBottom -你只需要得到漂移…

我们现在有一个原生javascript交集观察者API 从中我们可以检测元素，无论它们是否在视口中。

这里有一个例子

const el = document.querySelector('#el') const observer = new window.IntersectionObserver(([entry]) => { if (entry. isintersection) { console.log(输入) 返回 ｝ console.log(离开) }, { 根:空, 阈值:0.1，//设置偏移量0.1表示如果元素在视口中至少占10%，则触发 }) observer.observe (el); 身体{ 身高:300 vh; ｝ # el { margin-top: 100 vh; ｝ <div id="el">这是元素</div>

我发现这里公认的答案对于大多数用例来说过于复杂。这段代码很好地完成了工作(使用jQuery)，并区分了完全可见和部分可见的元素:

var element         = $("#element");
var topOfElement    = element.offset().top;
var bottomOfElement = element.offset().top + element.outerHeight(true);
var $window         = $(window);

$window.bind('scroll', function() {

    var scrollTopPosition   = $window.scrollTop()+$window.height();
    var windowScrollTop     = $window.scrollTop()

    if (windowScrollTop > topOfElement && windowScrollTop < bottomOfElement) {
        // Element is partially visible (above viewable area)
        console.log("Element is partially visible (above viewable area)");

    } else if (windowScrollTop > bottomOfElement && windowScrollTop > topOfElement) {
        // Element is hidden (above viewable area)
        console.log("Element is hidden (above viewable area)");

    } else if (scrollTopPosition < topOfElement && scrollTopPosition < bottomOfElement) {
        // Element is hidden (below viewable area)
        console.log("Element is hidden (below viewable area)");

    } else if (scrollTopPosition < bottomOfElement && scrollTopPosition > topOfElement) {
        // Element is partially visible (below viewable area)
        console.log("Element is partially visible (below viewable area)");

    } else {
        // Element is completely visible
        console.log("Element is completely visible");
    }
});

下面是检查给定元素在其父元素中是否完全可见的代码片段:

export const visibleInParentViewport = (el) => {
  const elementRect = el.getBoundingClientRect();
  const parentRect = el.parentNode.getBoundingClientRect();

  return (
    elementRect.top >= parentRect.top &&
    elementRect.right >= parentRect.left &&
    elementRect.top + elementRect.height <= parentRect.bottom &&
    elementRect.left + elementRect.width <= parentRect.right
  );
}

我尝试了Dan的答案，然而，用于确定边界的代数意味着元素必须既≤视口大小，又完全在视口内才能为真，很容易导致假否定。如果你想确定一个元素是否在视口中，ryanve的答案是接近的，但被测试的元素应该与视口重叠，所以试试这个:

function isElementInViewport(el) {
    var rect = el.getBoundingClientRect();

    return rect.bottom > 0 &&
        rect.right > 0 &&
        rect.left < (window.innerWidth || document.documentElement.clientWidth) /* or $(window).width() */ &&
        rect.top < (window.innerHeight || document.documentElement.clientHeight) /* or $(window).height() */;
}