在滚动条到达底部之前做一些 100px 的事情 [英] Do something 100px before the scrollbar reaches bottom

问题描述

我有以下 Javascript，当滚动条到达页面底部时，警报会按预期显示.

I have the below Javascript, and the alert shows up as it is supposed to when the scrollbar hits the bottom of the page.

但是，我希望这种情况发生在 到达底部之前 100 像素.我该怎么做?

However, I would like this to happen 100 pixels before it reaches the bottom. How would I do that?

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

    alert("at bottom");

  }
}

推荐答案

$(window).scroll(function(){
  if($(window).scrollTop() + 100 > $(document).height() - $(window).height() ){

    alert("at bottom");

  }
});

使用 > 而不是 == 因为滚动事件偶尔会触发，因此您可以多次滚动超过该值而不会触发事件精确匹配.

Using > instead of == because the scroll event fires sporadically, so you may scroll past that value a bunch of times without the event ever firing when there's a precise match.

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