jQuery

Question

I'm making a system where a user clicks a button and their score increases. There is a counter which I would like to increase the value of using jQuery (so that the page does not need to refresh) when the button is clicked.

How would I go about this?

<script type="text/javascript" src="http://code.jquery.com/jquery-1.4.3.min.js"></script>
<script type="text/javascript">

$("#update").click(function() {
$("#counter")++;
}

</script>

#update is the button, #counter is the counter.

In php, ++ increases something's value. What's the jQuery equivalent?

Also, when the button is clicked, it needs to send a request which updates the score value in a mysql database as well, without the page refreshing. Does anyone know how I would do that?

Thanks a lot

UPDATE:

I've tried a few of the methods below, but nothing seems to work! Do I need to change anything else for it to work? I've created a test page for it:

<html>
<body>
<script type="text/javascript" src="http://code.jquery.com/jquery-1.4.3.min.js"></script>
<script type="text/javascript">

var count = 0;

$("#update").click(function() {
    count++;
    $("#counter").html("My current count is: "+count);
}

</script>
<button id="update" type="button">Button</button>
<div id="counter">1</div>
</body>
</htlm>

Marcus Whybrow · Accepted Answer

You cannot use ++ on something which is not a variable, this would be the closest you can get:

$('#counter').html(function(i, val) { return +val+1 });

jQuery's html() method can get and set the HTML value of an element. If passed a function it can update the HTML based upon the existing value. So in the context of your code:

$("#update").click(function() {
    $('#counter').html(function(i, val) { return +val+1 });
}

DEMO: http://jsfiddle.net/marcuswhybrow/zRX2D/2/

When it comes to synchronising your counter on the page, with the counter value in your database, never trust the client! You send either an increment or decrement signal to you server side script, rather than a continuous value such as 10, or 23.

However you could send an AJAX request to the server when you change the HTML of your counter:

$("#update").click(function() {
    $('#counter').html(function(i, val) {
        $.ajax({
            url: '/path/to/script/',
            type: 'POST',
            data: {increment: true},
            success: function() { alert('Request has returned') }
        });
        return +val+1;
    });
}

jpea · Answer

$(document).ready(function() {
var count = 0;

  $("#update").click(function() {
    count++;
    $("#counter").html("My current count is: "+count);
  }

});

<div id="counter"></div>

Vadim · Answer

It's just

var counter = 0;

$("#update").click(function() {
   counter++;
});

jQuery - Increase the value of a counter when a button is clicked

Tags:

javascript

button

Taimur

3 Answers

Marcus Whybrow

jpea

Vadim

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