JSFiddle - React, Tailwind, and code Playground

HTML

<div id="div1">div 1</div>
<div id="div2">div 2<br /> next line</div>

CSS

#div1 {float: left; width: 20%; background: red}
#div2 {float: left; width: 80%; background: blue}

JavaScript

$(document).ready(function(){
        if($("#div1").height() >= $("#div2").height()){
            $("#div2").height( $("#div1").height() );
        } else {
            $("#div1").height( $("#div2").height() );
        }
    })