You will need to use javascript in your html document to make it work. You will find many source codes if you do a quick google search, understand and modify it according to our need.

Can you help me find some source code that's can help me?

Thanks!

Try this andrewu(dot)co(dot)uk/clj/countdown/

You can visit W3SCHOOLS about "countdown from the number 100 to zero" there are lots of tutorials about LOOP.

I hope it will help you.

Use one of the numerous javascript tutorials available online.

For example: 35+ Best Free jQuery Countdown Timer

[DELETED]