Countdown Timer

Count down to any moment — days, hours, minutes, seconds, ticking live.

Pick a date and watch the clock run down to it. You'll learn how to make something happen repeatedly over time with setInterval, and how to do arithmetic with dates.

What's inside

• Live days / hours / minutes / seconds display
• setInterval and clearInterval, done correctly
• Date math without a library
• A friendly "it's time!" state at zero
• Light & dark mode, no dependencies

Quickstart

$ curl -LO https://devai.io/downloads/countdown-timer.zip$ unzip countdown-timer.zip && cd countdown-timer$ open index.html   # or just double-click the file

Browse the code

The full source, exactly as the zip ships it.