JSFiddle - React, Tailwind, and code Playground

HTML

<div class="js-box">This is here</div>

CSS

*{margin:0px;padding:0;}

.js-box{
     width:100px;
    height:20px;
    border:1px solid red;
}

JavaScript

var myApp = { 

        e : $('.js-box'),
        addStyle : function(){
        myApp.e.css('height','200');
        },
        warn : function(){
        alert('WOOOOOoooOO');
        }  
};
myApp.addStyle();
myApp.warn();