What would you like or expect to see? A nice UI for making a timer

Countdown timer about lab.js HOT 1 OPEN

commented on May 27, 2024

Countdown timer

from lab.js.

Comments (1)

mcfarla9 commented on May 27, 2024

Please note that setInterval() does not keep accurate time. As a result, simply decrementing the countdownTime will result in errors. This may not matter for short countdowns using a large delay interval. But for large countdowns, or short delay intervals, the error becomes significant (as we here learned the hard way!).

Instead, always, always, update your countdownTime or whatever based upon a current reading of the clock. E.g., instead of

const delayInterval = 1000;
// Set the countdown time in milliseconds
var countdownTime = 60000; // 1 minute

// Update the countdown every 1 second
var countdown = setInterval(function() {
    countdownTime -= delayInterval;
    // other stuff goes here ...
}, delayInterval);

const delayInterval = 1000;
// Set the countdown time in milliseconds
const tDone = performance.now() + 60000;  // 1 minute from now

// Update the countdown every 1 second (more or less)
var countdown = setInterval(function() {
    var countdownTime = tDone - performance.now();
    // other stuff goes here ...
}, delayInterval);

from lab.js.

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