ericmbarnard/Knockout-Validation — pull request #112 by mmmmmmm (2012-08-10 10:58:06+00:00)
Title: Adding support for functions that format error messages.

Sample usage:

ko.validation.rules['maxPercent'] = {
validator: ...,
message: function(percent) { return 'Maximum ' + Globalize.format(percent / 100, 'P0') + '!'; }
};