JSFiddle - React, Tailwind, and code Playground

CSS

div { height: 50px; background: cornflowerblue; }
body p, body div, body span, body input, body button, body textarea, body a {
box-sizing: border-box;
-moz-box-sizing: border-box;
-webkit-box-sizing: border-box;
-khtml-box-sizing: border-box;
-o-box-sizing: border-box;
}

JavaScript

window.m = $("<div />").appendTo("body"); 
console.log(m.css("overflow"));
m.slideUp(); 
console.log(m.css("overflow")); 
m.slideDown(function(){
      console.log(m.css("overflow"));
});