faizyab
This is not a simple task, because if already your csv, excel, doc are created we can show them directly with the dropdown click event. But If you want to generate these files based on the event selection it is not at all a good approach. If you want to create csv, excel, doc files there are so many articles to create this type of files.
go for google
http://www.google.co.in/[
^]
If any idea behind your program, please elaborate it in your question.
Thanks
SP