JSFiddle - React, Tailwind, and code Playground

HTML

<div lang="en">ENGLISH!</div>
<div lang="pt">PORTUGA!</div>
<button lang="pt" onclick="ver.en()">Vizualizar em inglĂŞs</button>
<button lang="en" onclick="ver.pt()">View in portuguese</button>

JavaScript

if(!localStorage.lang){
    localStorage.lang="pt";
}
ver=new (function(alterar){
    this.en=function(){
        alterar("en");        
    }
    this.pt=function(){
        alterar("pt");
    }
})(function(tipo){
    localStorage.lang=tipo;
    var elementos=document.querySelectorAll("*[lang]");
    for(var i=0;i<elementos.length;i++){
        if(elementos[i].lang==tipo){
            elementos[i].style.display="";
        }else{
            elementos[i].style.display="none";
        }
    }
});
ver[localStorage.lang]();