JSFiddle - React, Tailwind, and code Playground

JavaScript

function addEvent(to, type, fn) {
    // Firefox, Safari, Chrome, Opera
    if (document.addEventListener) {
        to.addEventListener(type, fn, false);
    }
    // Microsoft ActiveX Scripts
    else if (document.attachEvent) {
        to.attachEvent('on' + type, fn);
    }
    // Last hope
    else {
        to['on' + type] = fn;
    }
}

addEvent(window, 'load', onDomLoaded);

function onDomLoaded() {
    alert('Im finished loading the entire window, your language is: ' + navigator.language);
}