The string.format function inside of validate is a quite useful one, and one that I had actually already written myself before I started to use jQuery.

Just a suggestion to include this version instead of the one currently there, for 2 reasons:

1) Code reuse (string formatting is very useful in localization)

2) Optimization: my version uses positional regex, and also can be used on any string (so that a string doesn't have to be marked with $.format, saving space in minimization)

3) Xml useage: my string.format version can also format a string using an XML source, quite useful for ajax calls

File attached. Thanks!