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jQuery UI button and some calculations

Submitted by: @import:stackexchange-codereview··
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calculationsjquerysomebuttonand

Problem

I have a list of checkboxes styled using JQuery UI as buttons. Each have a data-price attributem containing a price in this format: data-price="40.00", data-price="25.00" etc.

When the user "checks" a box, I am adding it's data-price to the totalPrice var. Every time another box is clicked, it's own data-price is added to the total. If the user unchecks a boxm, that value is taken away. I have tried to prevent the value from going under 0.00 as well.

I then output the totalPrice into a div - totalBox.


    totalPrice = 0.00;
    $(function() {
        var totalBox = $('#totalBox');

        $( ".styled" ).button().bind('click', function() {
            var packagePrice = $(this).attr('data-price');
            var cost = parseFloat(packagePrice);

            if(totalPrice>=0.00) {
                if($(this).is(':checked')) {
                    totalPrice += cost;
                } else {
                    totalPrice -= cost;
                }
            }

            totalBox.html('Total:
                           £' 
                           + totalPrice.toFixed(2) + ''
            );
        });
    });


I imagine there are some optimisations here - any thoughts?

Solution

When working with prices, then in my opinion it's usually a good idea to avoid floating point numbers. Binary rounding errors can easily strike unexpectedly any time.

Instead I'd suggest to work with integers (thus pennies) internally, and just add the decimal point for output.

An other unrelated point: I would move the hard-coded HTML in the script to the HTML document and only write the price.

Context

StackExchange Code Review Q#3164, answer score: 2

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