I understand how to work countdown timers and date timers to an extent (to a specified date i.e YYYY-MM-DD) but I'm working on a web development college project where I wish for one of my web pages (JSP file) to have a countdown timer with the number of seconds left in the day from when the web application launches. 

The web page will also include an Ajax function where the user can click a button and a random motivational message will appear (this particular piece of code I know, but it's just to give you an idea of why I want this countdown timer).