Format number with commas

pretty-number.js

var prettyNumber = function ( number ) {
	var number = ( number ).toString(),
		point = number.indexOf( '.' ),
		floatPart = '',
		out = [],
		stream;
	if ( -1 !== point ) {
		floatPart = number.substring( point );
		number = number.substring( 0, point );
	}
	stream = number.split( '' ).reverse();
	stream.forEach( function ( num, index ) {
		if ( index && 0 === index % 3 ) {
			out.push( ',' );
		}
		out.push( num );
	});
	return out.reverse().join( '' ) + floatPart;
}