docs: function (request, callback) {
              var form = request.form;
              form.target = "xIFrame" + request.id;
              form.action = request.url;
              form.method = request.method;
              if (request.headers["Content-Type"]) {
                  try {
                      // in IE 8, setting form.enctype directly does not work
                      // form.setAttribute works better (check PTR 07049566)
                      form.setAttribute("enctype", request.headers["Content-Type"]);
                  } catch (ex) {
                      // This might throw an exception in IE if the content type is invalid.
                  }
              }
              try {
                  form.submit();
              } catch (er) {
                  this.$logError(this.ERROR_DURING_SUBMIT, null, er);
                  this._deleteRequest(request);
                  ariaCoreIO._handleTransactionResponse({
                      conn : {
                          status : 0,
                          responseText : null,
                          getAllResponseHeaders : function () {}
                      },
                      transaction : request.id
                  }, callback, true);
              }
          }