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 thou

Answer 1

This will add thousand separators while retaining the decimal part of a given number:

function format(n, sep, decimals) {
    sep = sep || "."; // Default to period as decimal separator
    decimals = decimals || 2; // Default to 2 decimals

    return n.toLocaleString().split(sep)[0]
        + sep
        + n.toFixed(decimals).split(sep)[1];
}

format(4567354.677623); // 4,567,354.68

You could also probe for the locale's decimal separator with:

var sep = (0).toFixed(1)[1];