function printf( ) {	// Output a formatted string
	// 
	// + original by: Ash Searle (http://hexmen.com/blog/)
	// + improved by: Michael White (http://crestidg.com)
	var ret = this.sprintf.apply(this, arguments);
	document.write(ret);
	return ret.length;
}

printf("%01.2f", 123.1);