function TMainForm.GetJavascriptVariable(variable: string): Variant;
var
  Window: IHTMLWindow2;
  DispatchIdOfProperty: Integer;
  MyPropertyValue: OleVariant;
  Temp: TExcepInfo;
  Res: Integer;
  Params:TDispParams;
begin
  // get window interface
  Window:= (Browser.ControlInterface.Document as IHTMLDocument2).parentWindow;
  Assert(Assigned(Window));
  // get dispatch ID of our variable
  if (Window as IDispatchEx).GetDispID(PWideChar(variable), fdexNameCaseSensitive, DispatchIdOfProperty) = S_OK then
  begin
    // no parameters
    ZeroMemory(@Params, SizeOf(Params));
    // get value of our variable
    Res:=(Window as IDispatchEx).InvokeEx(DispatchIdOfProperty, LOCALE_USER_DEFAULT, DISPATCH_PROPERTYGET, @Params, MyPropertyValue, Temp, nil);
    if Res=S_OK then
    begin
      // voila - this should display the value
      result := MyPropertyValue;
    end else
      ShowMessage('Error reading property value');
  end
  else
    ShowMessage('Property not found');
end;