我正在寻找一种方法来查看元素是否即将进入视图，所以通过扩展上面的代码段，我设法做到了。我想我应该把这个留在这里，说不定能帮到谁

Elm =是视图中要检查的元素

scrollElement =你可以传递window或者带有滚动的父元素

Offset =如果你想让它在元素在屏幕前200px处触发，那么传递200

isscro冷景的功能(elem, scrole，抵消) { var $elem = $(elem); var $window = $); var docViewTop = $window.scrollTop(); var docViewBottom = docViewTop + $window.height(); var elemTop = $elem.抵消()top; var elemBottom = elemTop + $elem.height() 归来((elemBottom +) > = docViewBottom) &&偏移(elemTop-offset) < = docViewTop) | | ((elemBottom-offset) < = docViewBottom) && (elemTop +偏移)> = docViewTop); 的

制作了一个简单的插件，用于检测元素在可滚动容器中是否可见

    $.fn.isVisible = function(){

      var win;
      if(!arguments[0])
      {
        console.error('Specify a target;');
        return false;
      }
      else
      {
        win = $(arguments[0]);
      }
      var viewport = {};
      var bounds = this.offset();
      bounds.right = bounds.left + this.outerWidth();
      bounds.bottom = bounds.top + this.outerHeight();
      viewport.bottom = win.height() + win.offset().top;
      return (!( bounds.top > viewport.bottom) && (win.offset().top < bounds.bottom));
    };

像这样调用$('elem_to_check').isVisible('scrollable_container');

希望能有所帮助。

简单的检查元素(el)是否在可滚动的div (holder)中可见

function isElementVisible (el, holder) {
  holder = holder || document.body
  const { top, bottom, height } = el.getBoundingClientRect()
  const holderRect = holder.getBoundingClientRect()

  return top <= holderRect.top
    ? holderRect.top - top <= height
    : bottom - holderRect.bottom <= height
}

使用jQuery:

var el = $('tr:last').get(0);
var holder = $('table').get(0);
var isVisible = isElementVisible(el, holder);

在打印稿

  private readonly isElementInViewPort = (el: HTMLElement): boolean => {
      const rect = el.getBoundingClientRect();
      const elementTop = rect.top;
      const elementBottom = rect.bottom;
      const scrollPosition = el?.scrollTop || document.body.scrollTop;
      return (
        elementBottom >= 0 &&
        elementTop <= document.documentElement.clientHeight &&
        elementTop + rect.height > elementTop &&
        elementTop <= elementBottom &&
        elementTop >= scrollPosition
      );

};

这里有一种使用Mootools实现相同目标的方法，可以是水平的、垂直的或两者都有。

Element.implement({
inVerticalView: function (full) {
    if (typeOf(full) === "null") {
        full = true;
    }

    if (this.getStyle('display') === 'none') {
        return false;
    }

    // Window Size and Scroll
    var windowScroll = window.getScroll();
    var windowSize = window.getSize();
    // Element Size and Scroll
    var elementPosition = this.getPosition();
    var elementSize = this.getSize();

    // Calculation Variables
    var docViewTop = windowScroll.y;
    var docViewBottom = docViewTop + windowSize.y;
    var elemTop = elementPosition.y;
    var elemBottom = elemTop + elementSize.y;

    if (full) {
        return ((elemBottom >= docViewTop) && (elemTop <= docViewBottom)
            && (elemBottom <= docViewBottom) && (elemTop >= docViewTop) );
    } else {
        return ((elemBottom <= docViewBottom) && (elemTop >= docViewTop));
    }
},
inHorizontalView: function(full) {
    if (typeOf(full) === "null") {
        full = true;
    }

    if (this.getStyle('display') === 'none') {
        return false;
    }

    // Window Size and Scroll
    var windowScroll = window.getScroll();
    var windowSize = window.getSize();
    // Element Size and Scroll
    var elementPosition = this.getPosition();
    var elementSize = this.getSize();

    // Calculation Variables
    var docViewLeft = windowScroll.x;
    var docViewRight = docViewLeft + windowSize.x;
    var elemLeft = elementPosition.x;
    var elemRight = elemLeft + elementSize.x;

    if (full) {
        return ((elemRight >= docViewLeft) && (elemLeft <= docViewRight)
            && (elemRight <= docViewRight) && (elemLeft >= docViewLeft) );
    } else {
        return ((elemRight <= docViewRight) && (elemLeft >= docViewLeft));
    }
},
inView: function(full) {
    return this.inHorizontalView(full) && this.inVerticalView(full);
}});

我在我的应用程序中有这样一个方法，但它不使用jQuery:

/* Get the TOP position of a given element. */
function getPositionTop(element){
    var offset = 0;
    while(element) {
        offset += element["offsetTop"];
        element = element.offsetParent;
    }
    return offset;
}

/* Is a given element is visible or not? */
function isElementVisible(eltId) {
    var elt = document.getElementById(eltId);
    if (!elt) {
        // Element not found.
        return false;
    }
    // Get the top and bottom position of the given element.
    var posTop = getPositionTop(elt);
    var posBottom = posTop + elt.offsetHeight;
    // Get the top and bottom position of the *visible* part of the window.
    var visibleTop = document.body.scrollTop;
    var visibleBottom = visibleTop + document.documentElement.offsetHeight;
    return ((posBottom >= visibleTop) && (posTop <= visibleBottom));
}

编辑:此方法适用于I.E.(至少版本6)。请阅读评论以了解FF的兼容性。