I'm currently creating a page where people can plan a trip. Based on dates they can choose for a location. I want to show all these decisions in some kind of log file :
LOGFILE:
1 - June 17 - Fly to Amsterdam
2 - June 18 - Train to Brussels
etc.
Everytime a button is clicked some text need to be added to this logfile.
goose is right. You need to use some server-side language for writing data in database or a file. Additionally, you can search from the Internet complete scripts about Log filing etc.
I'll move this thread to server-side forum. There are qualified members to assist you further.