JSFiddle - React, Tailwind, and code Playground

HTML

<div id = "body">
    <div id = "wrapper"></div>
    <div id = "inner"></div>    
</div>

CSS

#wrapper{background:red;
         width:100px;
         height:100px;}

#inner{
    position:absolute;
    background:green;
    width:50px;
    height:100px;
    margin:0;padding:0;
}

#body{position:relative;}

JavaScript

var rect = document.getElementById("wrapper").getBoundingClientRect();

$("#inner").css({ 'top': String($(window).scrollTop()+rect.top)+"px" });

width_inner = $("#inner").width();

$("#inner").css({ 'left': String($(window).scrollLeft()+rect.right-width_inner)+"px" });