Take the value of an input and return alert

Question

I’m trying to return a value from an input that receives the value of a variable that also receives the value of a small equation, but I’m not getting it.

The code is like this:

function calcularimc() {
    var formulario = document.getElementById('formulario');

    var quilos = +formulario.quilos.value;
    var metros = +formulario.metros.value;
    var centimetros = +formulario.centimetros.value;

    var altura = (metros * 100 + centimetros)/100;

    var imc = quilos / (altura * altura);

        if (imc <= 25) {
        alert(ok);
    }

    formulario.imc.value = imc.toFixed(2);

}
]

Obs: when I withdraw the part from the if, it returns to do the calculation and present the result.

Guys, the first mistake was that I didn’t leave a string in quotes. Second, is that I needed to put several conditions if and if Else. Stayed like this:

<form id="formulario">
    <fieldset>
        <legend>Cálculo do IMC</legend>

        <label for="quilos">Quilos:</label>
        <input type="text" name="quilos" />

        <label for="metros">Metros:</label>
        <input type="text" name="metros" />

        <label for="centimetros">Centímetros:</label>
        <input type="text" name="centimetros" />

        <label  for="imc">IMC:</label>
        <input  type="text" name="imc" disabled="disabled" />

    <a href="#" onclick="calcularimc();">calcular</a>
    </fieldset>
</form>

Function calcularimc() { var formulario = Document.getElementById('formulario');

var quilos = +formulario.quilos.value;
var metros = +formulario.metros.value;
var centimetros = +formulario.centimetros.value;

var altura = (metros * 100 + centimetros)/100;

var imc = quilos / (altura * altura);

if (imc <= 18.5 ) {
    alert('Abaixo do peso!');
} else if (imc > 18.6 && imc < 24.9) {
    alert('Peso ideal');
} else if (imc >= 25 && imc < 29.9){
    alert('Levemente acima');
} else if (imc > 30 && imc < 34.9) {
    alert('Obesidade grau 1');
} else if (imc > 35 && imc < 39.9) {
    alert('Obesidade grau 2');
} else if (imc > 40) {
    alert('Obesidade grau 3');
}

formulario.imc.value = imc.toFixed(2);

}

Answer 1

The problem is in alert:

alert(ok);

Where ok is not a variable. The correct thing would be to put it between quotes, single or double:

alert("ok"); or alert('ok');

When arriving at this ready your script does not proceed because it gives error of undefined variable.

Complementing, When you put a word in the code without quotation marks, the code assumes that it is an object (variable, function...) and not a text. Objects must be declared, otherwise results in error.

Answer 2

The previous answer is correct, but apparently there is an error in the calculation of the BMI, take a look at this. As I had already begun to answer the question I will publish a code I had made based on your.

function calcularimc() {
   var quilos = parseInt(document.getElementById("quilos").value);
   var metros = parseInt(document.getElementById("metros").value);
   var centimetros = parseInt(document.getElementById("centimetros").value);

   var altura = (metros*100 + centimetros)/100;
   var imc = quilos / (altura * altura);
   console.log(imc);
   if(imc <= 18.5){
      document.getElementById("resultado").innerHTML = 'Abaixo do peso';
   }else if(imc <= 24.9){
      document.getElementById("resultado").innerHTML = 'Peso normal';
   }else if(imc <= 29.9){
      document.getElementById("resultado").innerHTML = 'Peso em excesso';
   }else if(imc > 29.9){
      document.getElementById("resultado").innerHTML = 'Obesidade';
   }
}

<form id="formulario">
  <input type="text" id="quilos" placeholder="Quilos">
  <input type="text" id="metros" placeholder="Metros">
  <input type="text" id="centimetros" placeholder="Centímetros">
  <button type="button" onclick="calcularimc()">Calcular</button>
  <br><br>
  <div id="resultado"></div>
</form>