Lightweight jQuery Mobile validation plugin

Recently I needed a validation plugin for jQuery Mobile. I tried the existing plugins, but I could not get them to work. I quickly wrote one that served my purpose. It’s very simple. Currently it only supports required fields. I looked into expanding it, but have not needed it. Please use it however you see fit.

Usage:

$("form#loginForm").validate();

Plugin:

(function ($) {

    $.fn.validate = function () {
        var items = $(this).find('[class~="required"]');

        var isValid = true;

        items.each(function () {
            var self = $(this);

            self.blur(function () {
                var field = $(this);

                if (field.val().length == 0) {

                    isValid = false;

                    var siblings = field.siblings('label[class~="field-validation-invalid"]');

                    if (siblings.length == 0) {
                        var error = $('<label>')
                            .addClass('field-validation-invalid field-validation-error')
                            .text('This field is required');
                        field.after(error);
                    }
                } else {

                    var errorMessage = field.siblings('label[class~="field-validation-invalid"]').get(0);
                    errorMessage = $(errorMessage);
                    errorMessage.remove();
                    errorMessage.text('');
                }

            });
        });

        var buttons = $(this).find('[type="submit"]');

        buttons.each(function () {
            var button = $(this);

            button.click(function () {

                //reset the value, otherwise it's stuck in false mode forever.
                isValid = true;

                items.each(function () {
                    var self = $(this);

                    self.blur();
                });

                if (!isValid) {

                    return false;
                }
            });
        });

    };
})(jQuery);