JSFiddle - React, Tailwind, and code Playground

HTML

<form id="formulario" name="formulario">
    <input type="text" name="Nombre" id="Nombre" autofocus />
    <input type="text" name="Apellido" id="Apellido" />
    <input type="text" name="Ciudad" id="Ciudad" />
    <select name="Promocion" id="Promocion">
        <option value="1">Promo 1</option>
        <option value="2">Promo 2</option>
        <option value="3">Promo 3</option>
    </select>
    <input type = "submit" value = "Listar" />
</form>

CSS

input{
    display: block;
}

JavaScript

var form = document.getElementById("formulario"),
    elementos = form.elements,
    total = elementos.length;

form.addEventListener("submit", function(e){
    e.preventDefault();
    for (i = 0; i < total; i++)
        if (elementos[i].getAttribute("type") != "submit")
            document.body.innerHTML += elementos[i].id + ": " + elementos[i].value + "<br />";
}, false);