JSFiddle - React, Tailwind, and code Playground

HTML

<form id="form0">
    <input id="input0" placeholder="How Much?" />
</form>

JavaScript

var result = 0;
var input = document.getElementById("input0");
var form = document.getElementById("form0");


form.addEventListener("submit", function (e) {
    e.preventDefault();
});

input.addEventListener("keydown", function (e) {
    if (e.keyCode == 13) {
        addMyNumber();
    }
});


var addMyNumber = function () {
    window.alert('fai qualcosa con addMyNumber');
}