Calculo escalao

by ctanunes

HTML

<!doctype html>
<html lang="en">

<head>
    <title>Ficha6</title>
    <!-- Required meta tags -->
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">

    <!-- Bootstrap CSS -->
    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm"
        crossorigin="anonymous">
</head>

<body>
    <div class="container">
        <h1 class="mt-5 pb-3 font-weight-light">Cálculo de Escalão e IRC</h1>

        <form class="needs-validation" onsubmit="calcular()" novalidate>
            <div class="form-group">
                <label for="nomeEmpresa">Insira o nome da empresa</label>
                <input type="text" class="form-control" id="nomeEmpresa" placeholder="Nome Empresa" required>
                <div class="valid-feedback">
                    Bom nome!
                </div>
            </div>
            <div class="form-group">
                <label for="lucro">Insira o valor do lucro (euros)</label>
                <input type="number" class="form-control" id="lucro" min="0" placeholder="Lucro" required>
                <div class="invalid-feedback">
                    Insira um valor positivo!
                </div>
            </div>
            <div class="form-group">
                <label for="lucro">Escalão</label>
                <input type="text" class="form-control" id="escalao" readonly>
            </div>
            <div class="form-group">
                <label for="lucro">Taxa de IRC</label>
                <input type="text" class="form-control" id="taxa" readonly>
            </div>
            <div class="form-group">
                <label for="lucro">Valor imposto (euros)</label>
                <input type="text" class="form-control" id="imposto" readonly>
            </div>
            <button type="clean" class="btn btn-primary mb-2 mr-3"...