Add instead of concatenating number to an input value

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I don’t know if I made myself clear, but in the javascript code below, I want every time I click the button, a sum occurs, but I’m only able to concatenate. Thank you!

function somar(){
    document.getElementById("valorSomado").value += 80;
}
<button onclick="somar();">Somar</button>

<input type="text" id="valorSomado">

javascript

1 answer

5


The value of the input is read as String, you have to convert into Number to add instead of concatenate.

You can do it like this:

var somar = (function(el) {
    return function() {
        el.value = Number(el.value) + 80;
    }
})(document.getElementById("valorSomado"));

jsFiddle: https://jsfiddle.net/co29oovs/

or using global space:

var somado = document.getElementById("valorSomado");
function somar() {
    somado.value = Number(somado.value) + 80;
}
  • 1

    It worked, thank you very much!

  • A cool tip is to use typeof to check the variable type.

  • 1

    @Mauroalexandre In this case do not need, because the value field will always be string.

  • @Freneticfx great! If you want you can click and mark the answer as "accept".

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