Question

Good evening, folks.

I've been studying the foundations of JS and i got stuck with the following code, where the HTML page is supposed to receive a value in metters:

    <!DOCTYPE html>
<head>
    <meta charset="utf8">
</head>
<html>
<title>Exercícios js</title>
    <body>
        <p>Insira os dados: </p> <input type="text" name="dados" id="dados" placeholder="Digite a altura em metros">
        <button type="button" id="btn-click" onclick="conversor()">Converter !</button>
        <script type="text/javascript" src="scripts/motor.js">
            document.getElementById("btn-click").addEventListener("click");            

        </script>
    </body>
</html>

And with a function called conversor() within a separate .js, it's supposed to return the value in feet:

var pes = (document.getElementById("dados")) * 0.305;

function conversor(){


    alert('A altura em metros é: ' + (pes)). parseFloat(value);
}

The page alert says 'undefined'. My clue is that I'm trying to retrieve text inputs and then multiply it to a floating point number. You can see it by my attempt of using parseFloat...

That's the only clue I had. What is wrong with the above code?

Answer 1

There are some mistake in your code:

Did not set event handle to click event.

document.getElementById("btn-click").addEventListener("click", conversor);

Did not get value of document.getElementById("dados").value

0(document may be your typo.

function conversor(){
var pes = (document.getElementById("dados").value) * 0.305;
    alert('A altura em metros é: ' + (pes));
}

<!DOCTYPE html>
<head>
    <meta charset="utf8">
</head>
<html>
<title>Exercícios js</title>
    <body>
        <p>Insira os dados: </p> <input type="text" name="dados" id="dados" placeholder="Digite a altura em metros">
        <button type="button" id="btn-click" onclick="conversor()">Converter !</button>
        <script type="text/javascript" src="scripts/motor.js">
            document.getElementById("btn-click").addEventListener("click", conversor);            

        </script>
    </body>
</html>

JavaScript alert says 'undefined'

1 个答案: