code: function createURI(spec, originCharset, baseURI)
  {
    let iosvc = Cc["@mozilla.org/network/io-service;1"].
                getService(Ci.nsIIOService);
  
    return iosvc.newURI(spec, originCharset, baseURI);
  }
docs: Create a new URI
  
  @param {string} spec
  The URI string in UTF-8 encoding.
  @param {string} originCharset
  The charset of the document from which this URI string originated.
  @param {string} baseURI
  If null, spec must specify an absolute URI. Otherwise, spec may be
  resolved relative to baseURI, depending on the protocol.
  @return A URI object
  @type nsIURI