Javascript function stops working when adding int

Question

I'm making system where questions can be answered trough a select box system. It works so far

function changedValue(vraagId) {
    currentId = document.getElementById(vraagId+1).value;
    valueId = document.getElementById(vraagId).value;
    if (currentId == "") {
        document.getElementById(valueId+1).disabled = true;
        document.getElementById(valueId+2).disabled = true;
        document.getElementById(valueId+3).disabled = true;
        document.getElementById(valueId+4).disabled = true;
        document.getElementById(vraagId+1).value = valueId;
    }
    else {
        document.getElementById(valueId+1).disabled = true;
        document.getElementById(valueId+2).disabled = true;
        document.getElementById(valueId+3).disabled = true;
        document.getElementById(valueId+4).disabled = true;
        document.getElementById(currentId+1).disabled = false;
        document.getElementById(currentId+2).disabled = false;
        document.getElementById(currentId+3).disabled = false;
        document.getElementById(currentId+4).disabled = false;
        document.getElementById(vraagId+1).value = valueId;
    }
}
function removeValue(vraagId) {
    currentId = document.getElementById(vraagId+1).value;
    document.getElementById(currentId+1).disabled = false;
    document.getElementById(currentId+2).disabled = false;
    document.getElementById(currentId+3).disabled = false;
    document.getElementById(currentId+4).disabled = false;
    document.getElementById(vraagId+1).value = "";
    if (vraagId == 'vraag1') {
        document.getElementById('antwoord01').selected = true;
    }
    if (vraagId == 'vraag2') {
        document.getElementById('antwoord02').selected = true;
    }
    if (vraagId == 'vraag3') {
        document.getElementById('antwoord03').selected = true;
    }
    if (vraagId == 'vraag4') {
        document.getElementById('antwoord04').selected = true;
    }
}

But now I want to add a system that enables a button when all questions are answered. I've come up with a system that uses an int. As soon as a question is answered, it adds 1. As soon as a question is unanswered, it removes 1. However, when I add int beantwoord = 0; to my script it gives me the error

Uncaught ReferenceError: changedValue is not defined

How can I fix this?

Answer 1

JavaScript is dynamically-typed (variable can hold different types of data), so the following statement will throw an error:

int someVar = 1;

Instead, declare your variable using var , eg

var someVar = 1;