forked to add test that selector points to a form in the first place; if it's an [] then the function will throw an exception

jquery.validate.unobtrusive.dynamic.js

/// <reference path="../jquery-1.7.js" />
/// <reference path="../jquery.validate.js" />
/// <reference path="../jquery.validate.unobtrusive.js" />

// Originally by XHalent, @xhalent
// http://xhalent.wordpress.com/
// http://xhalent.wordpress.com/2011/01/24/applying-unobtrusive-validation-to-dynamic-content/

// Modified by Joel Purra
// http://joelpurra.com/
// https://gist.github.com/gists/2360001

(function ($, undefined) {
    $.validator.unobtrusive.parseDynamicContent = function (selector) {

        var $selector;

        if (selector instanceof jQuery) {
            $selector = selector;
        }
        else {
            $selector = $(selector);
        }

        if ($selector.length == 0) {
            return;
        }

        //use the normal unobstrusive.parse method
        $.validator.unobtrusive.parse($selector);

        //get the relevant form
        var form = $selector.first().closest('form');

        //get the collections of unobstrusive validators, and jquery validators
        //and compare the two
        var unobtrusiveValidation = form.data('unobtrusiveValidation');
        var validator = form.validate();

        if (unobtrusiveValidation.options && unobtrusiveValidation.options.rules) {
            $.each(unobtrusiveValidation.options.rules, function (elname, elrules) {
                if (validator.settings.rules[elname] == undefined) {
                    var args = {};
                    $.extend(args, elrules);
                    args.messages = unobtrusiveValidation.options.messages[elname];
                    //edit:use quoted strings for the name selector
                    $("[name='" + elname + "']", $selector).rules("add", args);
                } else {
                    $.each(elrules, function (rulename, data) {
                        if (validator.settings.rules[elname][rulename] == undefined) {
                            var args = {};
                            args[rulename] = data;
                            args.messages = unobtrusiveValidation.options.messages[elname][rulename];
                            //edit:use quoted strings for the name selector
                            $("[name='" + elname + "']", $selector).rules("add", args);
                        }
                    });
                }
            });
        }
    };
})(jQuery);