JSFiddle - React, Tailwind, and code Playground

HTML

<div id="wrapper">
  <div id="content"></div>
</div>


<div id="data">HEHE</div>
<div id="data-2"></div>

CSS

#wrapper{
  height:100px;
  width:100%;
  overflow-x:auto;
}
#content{
  height:100%;
  width:200%;
  background:linear-gradient(to right, red , yellow);
}

JavaScript

var wrapper = document.getElementById("wrapper");
var content = document.getElementById("content");

console.log(wrapper.clientHeight);
console.log(content.clientHeight);


document.getElementById("data").textContent = wrapper.clientHeight;
document.getElementById("data-2").textContent = content.clientHeight;