A web page that contains a form using a select pull-down element. Once the user selects the desired option, the script will dynamically create another pull-down element whose contents will depend upon the visitor's first choice…
In other words: I would start with the first option being coded in html. When the user makes a choice, another option menu appears dynamically that contains choices that are directly related to the answer of the first choice. Once the user makes a second choice, the third option menu will appear with new choices that are dependent upon the second choice (and, of course, on the first choice…). Once the user has made 3 different choices. new element node is created and dynamically prints out the choices out to the screen.
There is function to create all of the dropdowns; the content of the select/option should be dependent upon what information is sent to the function.