Fixed position element inside div container only

问题

I have a fixed block element inside a container. On scrolling the fixed positioned element is going beyond the container. I understood fixed element will be positioned according to window vw. But is there any way to make sure fixed positioned element will get scrolled only upto container position. The fixed position element should not go beyond the container

The problem can be seen in the following.

https://codepen.io/anon/pen/dKLByX

I tried to fix the problem using the following:

if($(window).scrollTop()>1900){
    $('.fixed-ct').css({'bottom':'200px','top':'auto'});
}else if($(document).scrollTop() <=100) {
    $('.fixed-ct').css({'top':'10px','bottom':'auto'});
}else {
    $('.fixed-ct').css({'top':'0px','bottom':'auto'});
}

but sometimes the fixed container is at end because of bottom 200px it should be at top using top:0px on scroll and it should be inside the container itself.

回答1:

There you go, use position sticky inside .fixed-ct and add position:relative to .main-ct

.main-ct {
  width: 1000px;
  height:600px;
  border: 1px solid #000;
  position:relative;
}
.fixed-ct {
  position: sticky;
  width:100px;
  height:20px;
  background: red;
  top:10px;
}
.like-body {
  width: 100%;
  height:1300px;
}

<div class="like-body">
  <div class="main-ct">
    <div class="fixed-ct"></div>
  </div>
</div>

来源：https://stackoverflow.com/questions/51174427/fixed-position-element-inside-div-container-only