{countdown '2026-12-31 00:00'} writes the time left until the moment in words - 84 days, 3 hours - inside a <time class="pad-countdown"> whose datetime is the moment and whose title is the moment in full. The words start at the largest unit that is not zero and take units of them, a zero unit among them left out: 5 minutes, 12 seconds, 1 day. Once the moment has gone, the text of past= stands there instead - ended when not given.

Now is padNow (), so padNowFreeze () holds a test still, and now= counts from a given moment - how the first example here stays the same on every request. format= is the PHP date format of the title.

With live the element gets role="timer" and the moment in milliseconds, and a small script - written once a page, carrying the request's nonce when $padCsp asks for one - counts down every second from the browser's clock, the same way the server counts. Without a script the server's words stay as they are. A moment that is no date and units outside 1 to 4 are strict errors.