parseInt html string value

Question

Im trying to perform simple calculations using jQuery but I'm getting NaN as result.

Here is my javascript:

$(document).on('click','.button-group button:not(.done)', function(e){
        e.preventDefault();
        $(this).addClass('active');
        var votevalue = $(this).data('votevalue');
        var image_id = $('.mainimage').data('image_id');
        var votes = $('.mainimage').data('numvotes');
        var totalscore = $('.mainimage').data('totalscore');
            $.ajax({
                type: 'POST',
                url: '?a=vote',
                data: {
                    "votevalue" : votevalue,
                    "image_id" : image_id
                },
                success: function(){
                    var votes = parseInt(votes);
                    votes++;
                    var average = ((parseInt(totalscore) + parseInt(votevalue)) / votes);
                    $('#vote-incremenet').html(votes);
                    $('#display-average').html(average);
                    $('#display-average').show();
                    $('.button-group button').addClass('done');
                }
        }); // end ajax
}); // end click

What am I doing wrong?

Unrelated to your NaN issue, shouldn't you also be storing the new votes value back into $('.mainimage').data('numvotes')? Otherwise when another button is clicked it will use the old numvotes value for its calculation. — nnnnnn
– nnnnnn, Commented Nov 10, 2012 at 23:14
No all buttons are deactivated (.addClass('done')) after user first choice until next image. — user1683645
– user1683645, Commented Nov 10, 2012 at 23:26

Anirudh Ramanathan · Accepted Answer · 2012-11-11 00:12:27Z

3

When you use parseInt, be sure to pass (parseInt(str), radix)to prevent an automatic conversion to some other base.

If the input string begins with "0x" or "0X", radix is 16 (hexadecimal).

If the input string begins with "0", radix is eight (octal). This feature is non-standard, and some implementations deliberately do not support it (instead using the radix 10).

For this reason always specify a radix when using parseInt.

(MDN)

In your case, parseInt(varname, 10);

If the issue persists, it is likely you are passing an incorrect value to one of the variables you are using for calculation.

EDIT:

var votes = parseInt(votes); inside the call-back makes it a local variable. Hence,it has lost the value it was given outside. Do not redeclare it within the callback.

edited Nov 11, 2012 at 0:12

answered Nov 10, 2012 at 23:03

Anirudh Ramanathan

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2 Comments

user1683645 Over a year ago

Another thing I found out is that I was getting NaN when performing the calculation in the callback function. But when I moved the same calculation to before the ajax it displayed the numbers.

Anirudh Ramanathan Over a year ago

@user1683645 Try the same code you posted, with var votes = parseInt(votes); changed to just votes = parseInt(votes); in the success call-back.

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