Add commas to integers (2000000 -> 2,000,000) in javascript

intcomma.js

var intcomma = function(value) {
    // inspired by django.contrib.humanize.intcomma
    var origValue = String(value);
    var newValue = origValue.replace(/^(-?\d+)(\d{3})/, '$1,$2');
    if (origValue == newValue){
        return newValue;
    } else {
        return intcomma(newValue);
    }
};