[javascript] Javascript: Easier way to format numbers?

I'm trying to format various numbers on my page. These numbers either represent a price, a change in price, or a percentage. I know Javascript has functions to limit the number of decimal places, but is there any support for other types of formatting, such as grouping numbers with commas, controlling whether or not the +/- is shown, etc? Here's what I have so far:

var FORMATTER = {
    price       : function(value) { return '$' + value.toFixed(2); },
    pricePer    : function(value) { return (value * 100).toFixed(2) + '%'; },
    priceChg    : function(value) { return (value >= 0 ? '+' : '-') + '$' + Math.abs(value).toFixed(2); }
};

It works OK, but it'd like to add commas to the 'price' formatter, and you can see that there's a hack in the 'priceChg' formatter where I try to move the +/- sign in front of the '$' sign.

Basically, I'm hoping there is some library out there (jQuery is OK) that emulates Java's DecimalFormat class.

Just finished up a js library for formatting numbers Numeral.js. It handles decimals, dollars, percentages and even time formatting.

Also try dojo.number which has built-in localization support. It is a much closer analog to Java's NumberFormat/DecimalFormat

Here's the YUI version if anyone's interested:

http://developer.yahoo.com/yui/docs/YAHOO.util.Number.html

var str = YAHOO.util.Number.format(12345, { thousandsSeparator: ',' } );

No, there is no built-in support for number formatting, but googling will turn up loads of code snippets that will do this for you.

EDIT: I missed the last sentence of your post. Try http://code.google.com/p/jquery-utils/wiki/StringFormat for a jQuery solution.