The `url` module provides functionality for the parsing and retrieving of URLs. @class @constructor The URL constructor creates an object that represents a URL, verifying that the provided string is a valid URL in the process. Any API in the SDK which has a URL parameter will accept `URL` objects, not raw strings, unless otherwise noted. @param source {string} A string to be converted into a URL. If `source` is not a valid URI, this constructor will throw an exception. @param [base] {string} An optional string used to resolve relative `source` URLs into absolute ones. @property {string} The name of the protocol in the URL. @property {string} The username:password part of the URL, `null` if not present. @property {string} The host of the URL, `null` if not present. @property {integer} The port number of the URL, `null` if none was specified. @property {string} The path component of the URL. @method Returns a string representation of the URL. @returns {string} The URL as a string. @function Attempts to convert the given URL to a native file path. This function will automatically attempt to resolve non-file protocols, such as the `resource:` protocol, to their place on the file system. An exception is raised if the URL can't be converted; otherwise, the native file path is returned as a string. @param url {string} The URL, as a string, to be converted. @returns {string} The converted native file path as a string. @function Converts the given native file path to a `file:` URL. @param path {string} The native file path, as a string, to be converted. @returns {string} The converted URL as a string. @function Checks the validity of a URI. `isValidURI("http://mozilla.org")` would return `true`, whereas `isValidURI("mozilla.org")` would return `false`. @param uri {string} The URI, as a string, to be tested. @returns {boolean} A boolean indicating whether or not the URI is valid. @class @constructor The DataURL constructor creates an object that represents a data: URL, verifying that the provided string is a valid data: URL in the process. @param uri {string} A string to be parsed as Data URL. If is not a valid URI, this constructor will throw an exception. @property {string} The MIME type of the data. By default is an empty string. @property {object} An hashmap that contains the parameters of the Data URL. By default is an empty object. @property {boolean} Defines the encoding for the value in `data` property. @property {string} The string that contains the data in the Data URL. If the `uri` given to the constructor contains `base64` parameter, this string is decoded. @method Returns a string representation of the Data URL. If `base64` is `true`, the `data` property is encoded using base-64 encoding. @returns {string} The URL as a string.