Protocol and Content Handlers

interface ClientInformation {

  readonly attribute boolean onLine;

  void registerProtocolHandler(in DOMString protocol, 
                               in DOMString uri, in DOMString title);
  void registerContentHandler(in DOMString mimeType, 
                              in DOMString uri, in DOMString title);

};

The registerProtocolHandler() method allows Web sites to register themselves as possible handlers for particular protocols. For example, an online fax service could register itself as a handler of the fax: protocol ([RFC2806]), so that if the user clicks on such a link, he is given the opportunity to use that Web site. Analogously, the registerContentHandler() method allows Web sites to register themselves as possible handlers for content in a particular MIME type. For example, the same online fax service could register itself as a handler for image/g3fax files ([RFC1494]), so that if the user has no native application capable of handling G3 Facsimile byte streams, his Web browser can instead suggest he use that site to view the image.