JSFiddle - React, Tailwind, and code Playground

HTML

<select><option value=test>Test</option></select>
<div id=t>CSS height: <span></span></div><div id=t2>Actual height: <span></span></div>

CSS

select{height:100px;max-height:20px;}

JavaScript

$(document).ready(function(){
    $('#t span').text($('select').css('height'));
    $('#t2 span').text($('select').height());
});