jQuery remote validation plugin

I wrote this jquery plugin to do remote validations on the server. The code self explanatory. When the field blurs (event is customisable), the plugin checks to see if there is a value and sends the request.

Nothing fancy, but since I'm relatively new to JavaScript I'm sure I might have missed a few things. I think the init method is a bit long in the tooth. I am also calling removeErrors() from a bunch of places in the method, but that might be necessary.

(function($, window, document, undefined) {

    var Validator = {
        init: function(options, elem) {
            var self = this;

            self.elem = elem;
            self.$elem = $(elem);
            self.url = options.url;

            // Attribute is the field name we want to validate: email, username, etc...
            // If the user passes it in the options, use it, if not, get it 
            // from the element's name attribute.
            // Maybe this can be a function in the options hash?
            // How do I call a function in the options hash?
            if (options.attribute) {
                self.attribute = options.attribute;
            } else {
                self.attribute = self.elem.getAttribute('name');
            }

            self.options = $.extend({}, $.fn.remoteValidate.options, options);
            self.validate();
        },

        validate: function() {
            var self = this;

            self.$elem.on(self.options.event, function() {
                // Store the current value of the field
                var value = self.$elem.val();

                // If the field is blank remove the errors
                if (!value) {
                    self.removeErrors();
                }

                // We only want to issue a request is
                // 1. The field has a value
                // 2. The value has changed from the last time.
                // So entering a value, blurring, then focusing and blurring
                // without changing the field should trigger one request.
                if (value && value !== self.attributeValue) {
                    self.attributeValue = value;

                    self.queryServer().success(function() {
                        self.removeErrors();

                        if (typeof self.options.onComplete === 'function') {
                            self.options.onComplete.apply(self.elem, arguments);
                        }
                    }).error(function(results) {
                        var errors = $.parseJSON(results.responseText).errors;

                        self.removeErrors();
                        self.buildFrag(errors);
                        self.displayErrors();

                        if (typeof self.options.onError === 'function') {
                            self.options.onError.apply(self.elem, arguments);
                        }
                    });
                }
            });
        },

        queryServer: function() {
            var self = this;

            return $.get(self.url, {
                attribute: self.attribute,
                format: 'json',
                value: self.$elem.val()
            });
        },

        removeErrors: function() {
            var self = this;
            self.$elem.siblings('.' + self.options.errorClass).remove();
        },

        displayErrors: function() {
            var self = this;
            self.$elem.after(self.errors);
        },

        buildFrag: function(errors) {
            var self = this;

            self.errors = $.map(errors, function(obj) {
                return $(self.options.wrapEachWith, {
                    class: self.options.errorClass
                }).append(obj);
            });
        }
    };

    $.fn.remoteValidate = function(options) {
        return this.each(function() {
            var validator = Object.create(Validator);
            validator.init(options, this);
        });
    };

    $.fn.remoteValidate.options = {
        wrapEachWith: '<p></p>',
        errorClass: 'error-message',
        event: 'blur',
        onComplete: null,
        onError: null,
        attribute: null
    };

})(jQuery, window, document);