15 minute looping countdown timer based on time of day

How can you make a countdown timer for an auto-webinar that starts every 15 minutes 24 hours a day?

The timer needs to reset every 15 minutes synchronized with the time of day. For example, if someone came to the site at 2:05 the timer would say there is 10 minutes left. If the visitor left the site at 2:07, then came back at 2:10, the timer would say there is 5 minutes left.

When the timer hits zero it stays at zero until the person refreshes the page or comes back another time.

I am doing this with leadpages.

Here's what it looks like Using the code provided by Nemo below:

with the custom CSS:

WITH CSS

And without Custom CSS:

WITHOUT CSS

Also, I've tried this on mobile and it does not resize so it cuts off the hours.

Thanks for all the help thus far.

https://stackoverflow.com/questions/66054266/15-minute-looping-countdown-timer-based-on-time-of-day February 05, 2021 at 05:43AM