JSFiddle - React, Tailwind, and code Playground

JavaScript

function getSize()
{
var w=window,d=document,e=d.documentElement;
var g=d.getElementsByTagName('body')[0];
var x=w.innerWidth||e.clientWidth||g.clientWidth;
var y=w.innerHeight||e.clientHeight||g.clientHeight;
return {width:x, height:y}
}
    
var size=getSize();
alert(size.width+" "+size.height)