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So I'm trying to create a counter using jQuery but I can't get it to work for some reason. I'm using 3 inputs. 1 number input and 2 buttons.

My html looks like this:

<html>

    <head>

        <link rel="stylesheet" type="text/css" href="style.css">

    </head>

    <body>

        <div id="title">
            <div id="middle">
                <div id="inner">Books</div> 
            </div>
        </div>

        <input class="counter" type="number" value="0"></input>

        <input class="red" type="submit" value="-"></input>
        <input class="green" type="submit" value="+"></input>

        <script type="text/javascript" src="jquery-1.11.10.min.js"></script>
        <script type="text/javascript" src="script.js"></script>

    </body>

</html>

And this is my jQuery code:

$(document).ready(function(){

    var num = 0;

    $(".red").click(function(){
        num = $(".counter").val();
        num = num - 1;
        $(".counter").val(num);
    })

    $(".green").click(function(){
        num = $(".counter").val();
        num = num + 1;
        $(".counter").val(num);
    })

}

I can't seem to find what's wrong with my code.

So I'm trying to create a counter using jQuery but I can't get it to work for some reason. I'm using 3 inputs. 1 number input and 2 buttons.

My html looks like this:

<html>

    <head>

        <link rel="stylesheet" type="text/css" href="style.css">

    </head>

    <body>

        <div id="title">
            <div id="middle">
                <div id="inner">Books</div> 
            </div>
        </div>

        <input class="counter" type="number" value="0"></input>

        <input class="red" type="submit" value="-"></input>
        <input class="green" type="submit" value="+"></input>

        <script type="text/javascript" src="jquery-1.11.10.min.js"></script>
        <script type="text/javascript" src="script.js"></script>

    </body>

</html>

And this is my jQuery code:

$(document).ready(function(){

    var num = 0;

    $(".red").click(function(){
        num = $(".counter").val();
        num = num - 1;
        $(".counter").val(num);
    })

    $(".green").click(function(){
        num = $(".counter").val();
        num = num + 1;
        $(".counter").val(num);
    })

}

I can't seem to find what's wrong with my code.

  • javascript
  • jquery
  • html
  • counter
Share Improve this question asked Feb 5, 2014 at 19:18 RorrimRorrim 151 gold badge2 silver badges6 bronze badges 1
  • remove these: num = $(".counter").val(); – Malk Commented Feb 5, 2014 at 19:22
Add a ment  | 

3 Answers 3

Reset to default 4

Here I have use +, which Force the engine to implicitly convert it by applying a math operator to it;

Convert input value to number

num = +$(".counter").val();

DEMO

Additionally, You are missing closing ) of document ready handler.

I would also like to suggest you should use type="button" instead of type="submit"

The reason it's failing is because the val() is returned as a string and the + is doing string concatenation, not addition.

However, since you already have the value stored in a variable, you really don't need to pull the value from the input each time. Here's a simpler version:

http://jsfiddle/bcHWa/

var num = 0;

$(".red").click(function () {
    $(".counter").val(--num);
})

$(".green").click(function () {
    $(".counter").val(++num);
})

num = $(".counter").val(); is going to be a string, therefore "1" + "1" = "11"

Try:

 num = parseInt($(".counter").val());

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