JSFiddle - React, Tailwind, and code Playground

HTML

<input type='text' class='oi' value='999.999.999,99' />
<input type='button' class='formatar' value='formatar' />

JavaScript

var valorParaCalculo =  parseFloat(($(".oi").val()).replace(/\./g,"").replace(/,/g,".")); // output: 99999999.99

$(".formatar").click(function(){
    var valorParaCalculo =  parseFloat(($(".oi").val()).replace(/\./g,"").replace(/,/g,".")); // output: 99999999.99
    alert(valorParaCalculo);
});

alert(valorParaCalculo);