source: Dev/trunk/src/node_modules/tv4/tv4.async-jquery.js

// Provides support for asynchronous validation (fetching schemas) using jQuery
// Callback is optional third argument to tv4.validate() - if not present, synchronous operation
//     callback(result, error);
if (typeof (tv4.asyncValidate) === 'undefined') {
        tv4.syncValidate = tv4.validate;
        tv4.validate = function (data, schema, callback, checkRecursive, banUnknownProperties) {
                if (typeof (callback) === 'undefined') {
                        return this.syncValidate(data, schema, checkRecursive, banUnknownProperties);
                } else {
                        return this.asyncValidate(data, schema, callback, checkRecursive, banUnknownProperties);
                }
        };
        tv4.asyncValidate = function (data, schema, callback, checkRecursive, banUnknownProperties) {
                var $ = jQuery;
                var result = tv4.validate(data, schema, checkRecursive, banUnknownProperties);
                if (!tv4.missing.length) {
                        callback(result, tv4.error);
                } else {
                        // Make a request for each missing schema
                        var missingSchemas = $.map(tv4.missing, function (schemaUri) {
                                return $.getJSON(schemaUri).success(function (fetchedSchema) {
                                        tv4.addSchema(schemaUri, fetchedSchema);
                                }).error(function () {
                                        // If there's an error, just use an empty schema
                                        tv4.addSchema(schemaUri, {});
                                });
                        });
                        // When all requests done, try again
                        $.when.apply($, missingSchemas).done(function () {
                                var result = tv4.asyncValidate(data, schema, callback, checkRecursive, banUnknownProperties);
                        });
                }
        };
}