Just found accounting.js, which is a Javascript library “… for number, money and currency formatting …”. I love it so far. Check out the examples, then go check out the lib here and here.
// Default usage:
accounting.formatMoney(12345678); // $12,345,678.00 // European formatting (custom symbol and separators), could also use options object as second param: accounting.formatMoney(4999.99, "€", 2, ".", ","); // €4.999,99 // Negative values are formatted nicely, too: accounting.formatMoney(-500000, "£ ", 0); // £ -500,000 // Simple `format` string allows control of symbol position [%v = value, %s = symbol]: accounting.formatMoney(5318008, { symbol: "GBP", format: "%v %s" }); // 5,318,008.00 GBP