JSFiddle - React, Tailwind, and code Playground

HTML

<input type="number" value="" id="nmovimentos"/>

JavaScript

$(document).ready(function(){
    var oldValue = $("#nmovimentos").val();
  $("#nmovimentos").change(function(){
    var newValue = $(this).val();
    if (newValue > oldValue)
        alert("increase!");
     else
         alert("decrease!");
  });
});