我通过AJAX加载元素。其中一些只有当你向下滚动页面时才能看到。有什么方法可以知道元素现在是否在页面的可见部分?


当前回答

我需要检查可滚动DIV容器内元素的可见性

    //p = DIV container scrollable
    //e = element
    function visible_in_container(p, e) {
        var z = p.getBoundingClientRect();
        var r = e.getBoundingClientRect();

        // Check style visiblilty and off-limits
        return e.style.opacity > 0 && e.style.display !== 'none' &&
               e.style.visibility !== 'hidden' &&
               !(r.top > z.bottom || r.bottom < z.top ||
                 r.left > z.right || r.right < z.left);
    }

其他回答

如何

function isInView(elem){
   return $(elem).offset().top - $(window).scrollTop() < $(elem).height() ;
}

之后,一旦元素出现在视图中,你就可以触发你想要的任何东西

$(window).scroll(function(){
   if (isInView($('.classOfDivToCheck')))
      //fire whatever you what 
      dothis();
})

这对我来说很好

WebResourcesDepot在前段时间使用jQuery编写了一个滚动加载脚本。你可以在这里查看他们的现场演示。它们功能的关键在于:

$(window).scroll(function(){
  if  ($(window).scrollTop() == $(document).height() - $(window).height()){
    lastAddedLiveFunc();
  }
});

function lastAddedLiveFunc() { 
  $('div#lastPostsLoader').html('<img src="images/bigLoader.gif">');
  $.post("default.asp?action=getLastPosts&lastPostID="+$(".wrdLatest:last").attr("id"),
    function(data){
        if (data != "") {
          $(".wrdLatest:last").after(data);         
        }
      $('div#lastPostsLoader').empty();
    });
};

jquery scrollspy插件将允许您轻松做到这一点。 https://github.com/thesmart/jquery-scrollspy

$('.tile').on('scrollSpy:enter', function() {
    console.log('enter:', $(this).attr('id'));
});

$('.tile').on('scrollSpy:exit', function() {
    console.log('exit:', $(this).attr('id'));
});

$('.tile').scrollSpy();
function isScrolledIntoView(elem) {
    var docViewTop = $(window).scrollTop(),
        docViewBottom = docViewTop + $(window).height(),
        elemTop = $(elem).offset().top,
     elemBottom = elemTop + $(elem).height();
   //Is more than half of the element visible
   return ((elemTop + ((elemBottom - elemTop)/2)) >= docViewTop && ((elemTop + ((elemBottom - elemTop)/2)) <= docViewBottom));
}

用香草语回答:

function isScrolledIntoView(el) {
    var rect = el.getBoundingClientRect();
    var elemTop = rect.top;
    var elemBottom = rect.bottom;

    // Only completely visible elements return true:
    var isVisible = (elemTop >= 0) && (elemBottom <= window.innerHeight);
    // Partially visible elements return true:
    //isVisible = elemTop < window.innerHeight && elemBottom >= 0;
    return isVisible;
}