thanks for the quick response!
As for the website, I plan to build some simple static web pages, which include some texts, pictures, and animations. They are only for viewing as stimuli. But I did not work them out yet. Is it ok to use the iframe to reach these sites?
Moreover, if I randomize the order of these sites (stimulus), how can I know which answer belongs to which stimulus when I analyze data since the question is always the same?