selections not calculating hard to see if variable is set

here is my site http://iadprint.com/products?product=product%201

when you select a drop down for attribute19k the price value changes. but when you select other selections nothing happens. if you look in the source way on the bottom is the js that i put. whats supposed to happen is each time a selection is selected the value is accumulated to the total variable and displayed in the pricing span. but i cant see why it doesn't work. the variables are assigned but no calculations are occurring. can anyone see what i cant see?

thanks

ps here is the js

            var woattribute19k_price;
            var woattribute2_price;
            var woattribute3_price;
            var woattribute4_price;
            var woattribute5_price;












    $(document).ready(functi开发者_如何转开发on() { 



        $("#attribute19k").change(function() 
        {
            hash = $("#attribute19k").val(); 

            $.get("ajax.php", { id: hash },

                function(out)
                {
                    woattribute19k_price = out.price;
                    displayPrice();

                }, "json");

            });

        $("#attribute2").change(function() 
        {
            hash = $("#attribute2").val(); 

            $.get("ajax.php", { id: hash },

                function(out)
                {
                    woattribute2_price = out.price;
                    displayPrice();

                }, "json");

            });

        $("#attribute3").change(function() 
        {
            hash = $("#attribute3").val(); 

            $.get("ajax.php", { id: hash },

                function(out)
                {
                    woattribute3_price = out.price;
                    displayPrice();

                }, "json");

            });

        $("#attribute4").change(function() 
        {
            hash = $("#attribute4").val(); 

            $.get("ajax.php", { id: hash },

                function(out)
                {
                    woattribute4_price = out.price;
                    displayPrice();

                }, "json");

            });

        $("#attribute5").change(function() 
        {
            hash = $("#attribute5").val(); 

            $.get("ajax.php", { id: hash },

                function(out)
                {
                    woattribute5_price = out.price;
                    displayPrice();

                }, "json");

            });



});






    function displayPrice()
    {
        var total = 0;


        var qattribute19k = parseFloat((woattribute19k_price != null) ? woattribute19k_price : 0);
        total = parseFloat(total + qattribute19k).toFixed(2);



        var qattribute2 = parseFloat((woattribute2_price != null) ? woattribute2_price : 0);
        total = parseFloat(total + qattribute2).toFixed(2);



        var qattribute3 = parseFloat((woattribute3_price != null) ? woattribute3_price : 0);
        total = parseFloat(total + qattribute3).toFixed(2);



        var qattribute4 = parseFloat((woattribute4_price != null) ? woattribute4_price : 0);
        total = parseFloat(total + qattribute4).toFixed(2);



        var qattribute5 = parseFloat((woattribute5_price != null) ? woattribute5_price : 0);
        total = parseFloat(total + qattribute5).toFixed(2);




    $("#pricing span").text('$' + total);
    }

You have to use toFixed only at the end of displayPrice