JSFiddle - React, Tailwind, and code Playground

HTML

<input type="button" value="clicky" id="btn1" />
<div class="out">
    <div id="in">1</div>
</div>

CSS

.out{
     border:solid 5px orange;
     position:relative;
}

JavaScript

$('#btn1').click(function(){
    alert($('#in').position().top);
});