Add a thousands separator to a total with Javascript or jQuery?

Question

I have a function that sums a column of data in an html table. It does so admirably only I would like to have it put the commas in there that are needed to separate the thousands. Initially, you'll note, there are commas in the numbers being added. So that the function will add them, they are removed. How do I add the commas back in there?

<script type="text/javascript">
    function sumOfColumns(tableID, columnIndex, hasHeader) {
        var tot = 0;
        $("#" + tableID + " tr" + (hasHeader ? ":gt(0)" : ""))
          .children("td:nth-child(" + columnIndex + ")")
          .each(function() {
              tot += parseInt($(this).html().replace(',', ''));
          });
        return "Total Pounds Entered : " + tot;
    }
</script>

Answer 1

The $(this).html().replace(',', '') shouldn't actually modify the page. Are you sure the commas are being removed in the page?

If it is, this addCommas function should do the trick.

function addCommas(nStr) {
    nStr += '';
    var x = nStr.split('.');
    var x1 = x[0];
    var x2 = x.length > 1 ? '.' + x[1] : '';
    var rgx = /(\d+)(\d{3})/;
    while (rgx.test(x1)) {
        x1 = x1.replace(rgx, '$1' + ',' + '$2');
    }
    return x1 + x2;
}