JSFiddle - React, Tailwind, and code Playground

HTML

<div id="element">
    <p id="innerElement"> <!-- notice this inner element -->
        content<br />content<br />content<br />
        content<br />content<br />content<br />
        content<br />content<br />content<br />
    </p>
</div>

CSS

#element {
    height: 500px;
    width: 200px;
    background-color: red;
    overflow: hidden;
}
innerElement {
    margin: 0px;
    background-color: blue;
}

JavaScript

var innerHeight = $('#innerElement').height();
    alert("inner element's height = " + innerHeight + "px");