I have a stopwatch for a small tool here, I received most of the code from a previous question and I was going about trying to implement it, I began breaking it down and trying to understand it.
So far I think I understand most of it (Still some bits I am researching); however I was trying to adapt the code to my tool.
My requirements:
A start/stop button (a single button) - the value will change depending on if the timer is running or not.
A reset button - this will simply reset the timer to 00:00:00 and if the tool is running it will also stop it.
So far, the reset button is not configured, this is fine. The start and stop button works; however say I stopped the timer, and then started it again without resetting it, the timer just begins at 00:00:00 again, it will not continue from where it was paused.
It would be greatly appreciated if anyone would be able to explain how I could do this? I have tried the following:
Storing 'differenceInMillis for each loop of updateTimer() in a global variable, then subtracting the value from startTime = Date.now() each time the timer is restarted (This was suggested by a user in a previous question), I could not get this to work.
The code I have so far -
HTML (buttons and clock):
const outputElement = document.getElementById("outputt");
var startTime = 0;
var running = 0;
var splitcounter = 0;
function startstop() {
if (running == 0) {
running = 1;
startTime = Date.now();
startstopbutton.value = 'Stop';
document.getElementById("outputt").style.backgroundColor = "#2DB37B";
updateTimer();
} else {
running = 0;
// logTime();
startstopbutton.value = 'Start';
document.getElementById("outputt").style.backgroundColor = "#B3321B";
}
}
function updateTimer() {
if (running == 1) {
let differenceInMillis = Date.now() - startTime;
let {
hours,
minutes,
seconds
} = calculateTime(differenceInMillis);
let timeStr = `${pad(hours)}:${pad(minutes)}:${pad(seconds)}`;
outputElement.innerText = timeStr;
requestAnimationFrame(updateTimer);
}
}
function calculateTime(milliS) {
const SECONDS = 1000; // should be 1000 - only 10 to speed up the timer
const MINUTES = 60;
const HOURS = 60;
const RESET = 60;
let hours = Math.floor(milliS / SECONDS / MINUTES / HOURS);
let minutes = Math.floor(milliS / SECONDS / MINUTES) % RESET;
let seconds = Math.floor(milliS / SECONDS) % RESET;
return {
hours,
minutes,
seconds
};
}
function pad(time) {
return time.toString().padStart(2, '0');
}
<input id="startstopbutton" class="buttonZ" style="width: 120px;" type="button" name="btn" value="Start" onclick="startstop();">
<input id="resetbutton" class="buttonZ" style="width: 120px;" type="button" name="btnRst" id='btnRst' value="Reset" onclick="resetclock();" />
<div id="outputt" class="timerClock" value="00:00:00">00:00:00</div>
UPDATE new version - does not work however - session storage does not work at SO so will have to test elsewhere
const outputElement = document.getElementById("outputt");
var startTime = 0;
var running = 0;
var splitcounter = 0;
function startstop() {
if (running == 0) {
running = 1;
startTime = new Date(sessionStorage.getItem("time"))
if (isNaN(startTime)) startTime = Date.now();
startstopbutton.value = 'Stop';
document.getElementById("outputt").style.backgroundColor = "#2DB37B";
updateTimer();
} else {
running = 0;
logTime();
startstopbutton.value = 'Start';
document.getElementById("outputt").style.backgroundColor = "#B3321B";
}
}
function updateTimer() {
if (running == 1) {
let differenceInMillis = Date.now() - startTime;
sessionStorage.setItem("time", differenceInMillis)
let {
hours,
minutes,
seconds
} = calculateTime(differenceInMillis);
let timeStr = `${pad(hours)}:${pad(minutes)}:${pad(seconds)}`;
outputElement.innerText = timeStr;
requestAnimationFrame(updateTimer);
}
}
function calculateTime(milliS) {
const SECONDS = 1000; // should be 1000 - only 10 to speed up the timer
const MINUTES = 60;
const HOURS = 60;
const RESET = 60;
let hours = Math.floor(milliS / SECONDS / MINUTES / HOURS);
let minutes = Math.floor(milliS / SECONDS / MINUTES) % RESET;
let seconds = Math.floor(milliS / SECONDS) % RESET;
return {
hours,
minutes,
seconds
};
}
function pad(time) {
return time.toString().padStart(2, '0');
}
If you MUST use a date object, you will need to change
startTime = Date.now();
to
startTime = new Date(sessionStorage.getItem("time"))
if (isNaN(startTime)) startTime = Date.now();
and save the time
let differenceInMillis = Date.now() - startTime;
sessionStorage.setItem("time",differenceInMillis)
If not, use a counter instead of a date object
Also when you use a toggle as boolean, make it and use it as a boolean (good practice - not mandatory for this issue)
const outputElement = document.getElementById("outputt");
let counter = 0,
running = false,
splitcounter = 0,
lastTime = 0;
function startstop() {
running = !running;
startstopbutton.value = running ? 'Stop' : 'Start';
document.getElementById("outputt").style.backgroundColor = running ? "#2DB37B" : "#B3321B";
if (running) updateTimer(0)
}
function updateTimer(currentTime) {
if (running) requestAnimationFrame(updateTimer)
if (currentTime >= (lastTime + 1000)) {
counter++;
lastTime = currentTime;
let {
hours,
minutes,
seconds
} = calculateTime(counter * 1000);
let timeStr = `${pad(hours)}:${pad(minutes)}:${pad(seconds)}`;
outputElement.innerText = timeStr;
}
}
function calculateTime(milliS) {
const SECONDS = 1000; // should be 1000 - only 10 to speed up the timer
const MINUTES = 60;
const HOURS = 60;
const RESET = 60;
let hours = Math.floor(milliS / SECONDS / MINUTES / HOURS);
let minutes = Math.floor(milliS / SECONDS / MINUTES) % RESET;
let seconds = Math.floor(milliS / SECONDS) % RESET;
return {
hours,
minutes,
seconds
};
}
function pad(time) {
return time.toString().padStart(2, '0');
}
<input id="startstopbutton" class="buttonZ" style="width: 120px;" type="button" name="btn" value="Start" onclick="startstop();">
<input id="resetbutton" class="buttonZ" style="width: 120px;" type="button" name="btnRst" id='btnRst' value="Reset" onclick="resetclock();" />
<div id="outputt" class="timerClock" value="00:00:00">00:00:00</div>
New to coding! I want to make a simple countdown timer that counts down from 53 minutes. How can I format the output like "52:58" instead of "3178" (seconds)? Thanks! :)
This is what I have:
window.onload = function () {
var counter = 0;
var timeleft = 3180;
function convertSeconds(s) {
var min = floor (s / 60);
var sec = s % 60;
return min + ':' + sec;
}
function setup() {
var timer = document.getElementById("timer");
timer.innerHTML = (convertSeconds(timeleft - counter));
function timeIt() {
counter++;
timer.innerHTML = (convertSeconds(timeleft - counter));
}
setInterval(timeIt, 1000);
}
setup();
}
use Math.floor instead of floor. Your code already doing all what you want :)
window.onload = function () {
var counter = 0;
var timeleft = 3180;
function convertSeconds(s) {
var min = Math.floor (s / 60);
var sec = s % 60;
return min + ':' + sec;
}
function setup() {
var timer = document.getElementById("timer");
timer.innerHTML = (convertSeconds(timeleft - counter));
function timeIt() {
counter++;
timer.innerHTML = (convertSeconds(timeleft - counter));
}
setInterval(timeIt, 1000);
}
setup();
}
<div id="timer"></div>
You should use Math.floor()function to calculate values in minutes and
seconds.
I tried to build a countdown timer and it kind of worked, but when I changed the code to make it more readable and when I added the stop button function it got a bit buggy. I fiddled around a lot, but I can't get it working again.
The problem I have is, that the countdown starts from the time when the page has loaded and not from the number assigned to "sessTime".
Here is the code (i know it is a lot, sorry):
var startButton = document.getElementById('btnStart');
var stopButton = document.getElementById('btnStop');
var sessionTime = parseInt(document.getElementById('sessNum').innerHTML); //gets duration number
var sessLength = Date.parse(new Date()) + sessionTime * 60 * 1000;
startButton.onclick = function() {
if (!sessTimer) {
startButton.value="Stop";
var sessTimer = setInterval(runSess, 1000);
}else{
startButton.value="Start";
clearInterval(sessTimer);
}
};
function runSess() {
var timeLeft = sessLength - Date.parse(new Date());
var seconds = Math.floor((timeLeft / 1000) % 60);
var minutes = Math.floor((timeLeft / 1000 / 60) % 60);
var hours = Math.floor((timeLeft / (1000 * 60 * 60)) % 24);
document.getElementById("hours").innerHTML = ('0' + hours).slice(-2);
document.getElementById("minutes").innerHTML = ('0' + minutes).slice(-2);
document.getElementById("seconds").innerHTML = ('0' + seconds).slice(-2);
if (timeLeft <= 0) {
clearInterval(sessTimer);
}
}
This code is part of a codepen project of mine. Maybe the context helps to answer this question.
Thanks in advance, I really appreciate your help.
You have declared sessTimer inside the scope of your function.
startButton.onclick = function() {
if (!sessTimer) {
startButton.value="Stop";
var sessTimer = setInterval(runSess, 1000);
With the code above, every time you enter the function, sessTimer is undefined and you declare a new one. What you can do is the following :
var sessTimer = null;
startButton.onclick = function() {
if (!sessTimer) {
startButton.value="Stop";
sessTimer = setInterval(runSess, 1000);
}else{
startButton.value="Start";
clearInterval(sessTimer);
sessTimer = null;
}
};
Into you function, you also need to change your button :
if (timeLeft <= 0) {
startButton.value="Start";
clearInterval(sessTimer);
}
i want this my javascript code to to be able to be reading 3 hours countdown and also redirect to a new page after the countdown is complete
<script type="text/javascript">
// properties
var count = 0;
var counter = null;
window.onload = function() {
initCounter();
};
function initCounter() {
// get count from localStorage, or set to initial value of 1000
count = getLocalStorage('count') || 1000;
counter = setInterval(timer, 1000); //1000 will run it every 1 second
}
function setLocalStorage(key, val) {
if (window.localStorage) {
window.localStorage.setItem(key, val);
}
return val;
}
function getLocalStorage(key) {
return window.localStorage ? window.localStorage.getItem(key) : '';
}
function timer() {
count = setLocalStorage('count', count - 1);
if (count == -1) {
clearInterval(counter);
return;
}
var seconds = count % 60;
var minutes = Math.floor(count / 60);
var hours = Math.floor(minutes / 60);
minutes %= 60;
hours %= 60;
document.getElementById("timer").innerHTML = hours + "hours " + minutes + "minutes and " + seconds + " seconds left to complete this transaction"; // watch for spelling
}
</script>
<div id="timer"></div>
please help me make it better by making it been able to countdown to three hour and also redirect to another page after the countdown is complete
You didn't properly set total time. You set it to 16 minutes instead of 3 hours. Here is the working code (try it on JSFiddle):
var time = 60 * 60 * 3;
var div = document.getElementById("timer");
var t = Date.now();
var loop = function(){
var dt = (Date.now() - t) * 1e-3;
if(dt > time){
doWhateverHere();
}else{
dt = time - dt;
div.innerHTML = `Hours: ${dt / 3600 | 0}, Minutes: ${dt / 60 % 60 | 0}, Seconds: ${dt % 60 | 0}`;
}
requestAnimationFrame(loop);
};
loop();
Also, do not use setInterval and setTimeout for precise timing. These functions are volatile. Use Date.now() instead.
I want to use a simple countdown timer starting at 30 seconds from when the function is run and ending at 0. No milliseconds. How can it be coded?
var count=30;
var counter=setInterval(timer, 1000); //1000 will run it every 1 second
function timer()
{
count=count-1;
if (count <= 0)
{
clearInterval(counter);
//counter ended, do something here
return;
}
//Do code for showing the number of seconds here
}
To make the code for the timer appear in a paragraph (or anywhere else on the page), just put the line:
<span id="timer"></span>
where you want the seconds to appear. Then insert the following line in your timer() function, so it looks like this:
function timer()
{
count=count-1;
if (count <= 0)
{
clearInterval(counter);
return;
}
document.getElementById("timer").innerHTML=count + " secs"; // watch for spelling
}
I wrote this script some time ago:
Usage:
var myCounter = new Countdown({
seconds:5, // number of seconds to count down
onUpdateStatus: function(sec){console.log(sec);}, // callback for each second
onCounterEnd: function(){ alert('counter ended!');} // final action
});
myCounter.start();
function Countdown(options) {
var timer,
instance = this,
seconds = options.seconds || 10,
updateStatus = options.onUpdateStatus || function () {},
counterEnd = options.onCounterEnd || function () {};
function decrementCounter() {
updateStatus(seconds);
if (seconds === 0) {
counterEnd();
instance.stop();
}
seconds--;
}
this.start = function () {
clearInterval(timer);
timer = 0;
seconds = options.seconds;
timer = setInterval(decrementCounter, 1000);
};
this.stop = function () {
clearInterval(timer);
};
}
So far the answers seem to rely on code being run instantly. If you set a timer for 1000ms, it will actually be around 1008 instead.
Here is how you should do it:
function timer(time,update,complete) {
var start = new Date().getTime();
var interval = setInterval(function() {
var now = time-(new Date().getTime()-start);
if( now <= 0) {
clearInterval(interval);
complete();
}
else update(Math.floor(now/1000));
},100); // the smaller this number, the more accurate the timer will be
}
To use, call:
timer(
5000, // milliseconds
function(timeleft) { // called every step to update the visible countdown
document.getElementById('timer').innerHTML = timeleft+" second(s)";
},
function() { // what to do after
alert("Timer complete!");
}
);
Here is another one if anyone needs one for minutes and seconds:
var mins = 10; //Set the number of minutes you need
var secs = mins * 60;
var currentSeconds = 0;
var currentMinutes = 0;
/*
* The following line has been commented out due to a suggestion left in the comments. The line below it has not been tested.
* setTimeout('Decrement()',1000);
*/
setTimeout(Decrement,1000);
function Decrement() {
currentMinutes = Math.floor(secs / 60);
currentSeconds = secs % 60;
if(currentSeconds <= 9) currentSeconds = "0" + currentSeconds;
secs--;
document.getElementById("timerText").innerHTML = currentMinutes + ":" + currentSeconds; //Set the element id you need the time put into.
if(secs !== -1) setTimeout('Decrement()',1000);
}
// Javascript Countdown
// Version 1.01 6/7/07 (1/20/2000)
// by TDavid at http://www.tdscripts.com/
var now = new Date();
var theevent = new Date("Sep 29 2007 00:00:01");
var seconds = (theevent - now) / 1000;
var minutes = seconds / 60;
var hours = minutes / 60;
var days = hours / 24;
ID = window.setTimeout("update();", 1000);
function update() {
now = new Date();
seconds = (theevent - now) / 1000;
seconds = Math.round(seconds);
minutes = seconds / 60;
minutes = Math.round(minutes);
hours = minutes / 60;
hours = Math.round(hours);
days = hours / 24;
days = Math.round(days);
document.form1.days.value = days;
document.form1.hours.value = hours;
document.form1.minutes.value = minutes;
document.form1.seconds.value = seconds;
ID = window.setTimeout("update();", 1000);
}
<p><font face="Arial" size="3">Countdown To January 31, 2000, at 12:00: </font>
</p>
<form name="form1">
<p>Days
<input type="text" name="days" value="0" size="3">Hours
<input type="text" name="hours" value="0" size="4">Minutes
<input type="text" name="minutes" value="0" size="7">Seconds
<input type="text" name="seconds" value="0" size="7">
</p>
</form>
Just modified #ClickUpvote's answer:
You can use IIFE (Immediately Invoked Function Expression) and recursion to make it a little bit more easier:
var i = 5; //set the countdown
(function timer(){
if (--i < 0) return;
setTimeout(function(){
console.log(i + ' secs'); //do stuff here
timer();
}, 1000);
})();
var i = 5;
(function timer(){
if (--i < 0) return;
setTimeout(function(){
document.getElementsByTagName('h1')[0].innerHTML = i + ' secs';
timer();
}, 1000);
})();
<h1>5 secs</h1>
Expanding upon the accepted answer, your machine going to sleep, etc. may delay the timer from working. You can get a true time, at the cost of a little processing. This will give a true time left.
<span id="timer"></span>
<script>
var now = new Date();
var timeup = now.setSeconds(now.getSeconds() + 30);
//var timeup = now.setHours(now.getHours() + 1);
var counter = setInterval(timer, 1000);
function timer() {
now = new Date();
count = Math.round((timeup - now)/1000);
if (now > timeup) {
window.location = "/logout"; //or somethin'
clearInterval(counter);
return;
}
var seconds = Math.floor((count%60));
var minutes = Math.floor((count/60) % 60);
document.getElementById("timer").innerHTML = minutes + ":" + seconds;
}
</script>
For the sake of performances, we can now safely use requestAnimationFrame for fast looping, instead of setInterval/setTimeout.
When using setInterval/setTimeout, if a loop task is taking more time than the interval, the browser will simply extend the interval loop, to continue the full rendering. This is creating issues. After minutes of setInterval/setTimeout overload, this can freeze the tab, the browser or the whole computer.
Internet devices have a wide range of performances, so it's quite impossible to hardcode a fixed interval time in milliseconds!
Using the Date object, to compare the start Date Epoch and the current. This is way faster than everything else, the browser will take care of everything, at a steady 60FPS (1000 / 60 = 16.66ms by frame) -a quarter of an eye blink- and if the task in the loop is requiring more than that, the browser will drop some repaints.
This allow a margin before our eyes are noticing (Human = 24FPS => 1000 / 24 = 41.66ms by frame = fluid animation!)
https://caniuse.com/#search=requestAnimationFrame
/* Seconds to (STRING)HH:MM:SS.MS ------------------------*/
/* This time format is compatible with FFMPEG ------------*/
function secToTimer(sec){
const o = new Date(0), p = new Date(sec * 1000)
return new Date(p.getTime()-o.getTime()).toString().split(" ")[4] + "." + p.getMilliseconds()
}
/* Countdown loop ----------------------------------------*/
let job, origin = new Date().getTime()
const timer = () => {
job = requestAnimationFrame(timer)
OUT.textContent = secToTimer((new Date().getTime() - origin) / 1000)
}
/* Start looping -----------------------------------------*/
requestAnimationFrame(timer)
/* Stop looping ------------------------------------------*/
// cancelAnimationFrame(job)
/* Reset the start date ----------------------------------*/
// origin = new Date().getTime()
span {font-size:4rem}
<span id="OUT"></span>
<br>
<button onclick="origin = new Date().getTime()">RESET</button>
<button onclick="requestAnimationFrame(timer)">RESTART</button>
<button onclick="cancelAnimationFrame(job)">STOP</button>
You can do as follows with pure JS. You just need to provide the function with the number of seconds and it will do the rest.
var insertZero = n => n < 10 ? "0"+n : ""+n,
displayTime = n => n ? time.textContent = insertZero(~~(n/3600)%3600) + ":" +
insertZero(~~(n/60)%60) + ":" +
insertZero(n%60)
: time.textContent = "IGNITION..!",
countDownFrom = n => (displayTime(n), setTimeout(_ => n ? sid = countDownFrom(--n)
: displayTime(n), 1000)),
sid;
countDownFrom(3610);
setTimeout(_ => clearTimeout(sid),20005);
<div id="time"></div>
Based on the solution presented by #Layton Everson I developed a counter including hours, minutes and seconds:
var initialSecs = 86400;
var currentSecs = initialSecs;
setTimeout(decrement,1000);
function decrement() {
var displayedSecs = currentSecs % 60;
var displayedMin = Math.floor(currentSecs / 60) % 60;
var displayedHrs = Math.floor(currentSecs / 60 /60);
if(displayedMin <= 9) displayedMin = "0" + displayedMin;
if(displayedSecs <= 9) displayedSecs = "0" + displayedSecs;
currentSecs--;
document.getElementById("timerText").innerHTML = displayedHrs + ":" + displayedMin + ":" + displayedSecs;
if(currentSecs !== -1) setTimeout(decrement,1000);
}
// Javascript Countdown
// Version 1.01 6/7/07 (1/20/2000)
// by TDavid at http://www.tdscripts.com/
var now = new Date();
var theevent = new Date("Nov 13 2017 22:05:01");
var seconds = (theevent - now) / 1000;
var minutes = seconds / 60;
var hours = minutes / 60;
var days = hours / 24;
ID = window.setTimeout("update();", 1000);
function update() {
now = new Date();
seconds = (theevent - now) / 1000;
seconds = Math.round(seconds);
minutes = seconds / 60;
minutes = Math.round(minutes);
hours = minutes / 60;
hours = Math.round(hours);
days = hours / 24;
days = Math.round(days);
document.form1.days.value = days;
document.form1.hours.value = hours;
document.form1.minutes.value = minutes;
document.form1.seconds.value = seconds;
ID = window.setTimeout("update();", 1000);
}
<p><font face="Arial" size="3">Countdown To January 31, 2000, at 12:00: </font>
</p>
<form name="form1">
<p>Days
<input type="text" name="days" value="0" size="3">Hours
<input type="text" name="hours" value="0" size="4">Minutes
<input type="text" name="minutes" value="0" size="7">Seconds
<input type="text" name="seconds" value="0" size="7">
</p>
</form>
My solution works with MySQL date time formats and provides a callback function. on complition.
Disclaimer: works only with minutes and seconds, as this is what I needed.
jQuery.fn.countDownTimer = function(futureDate, callback){
if(!futureDate){
throw 'Invalid date!';
}
var currentTs = +new Date();
var futureDateTs = +new Date(futureDate);
if(futureDateTs <= currentTs){
throw 'Invalid date!';
}
var diff = Math.round((futureDateTs - currentTs) / 1000);
var that = this;
(function countdownLoop(){
// Get hours/minutes from timestamp
var m = Math.floor(diff % 3600 / 60);
var s = Math.floor(diff % 3600 % 60);
var text = zeroPad(m, 2) + ':' + zeroPad(s, 2);
$(that).text(text);
if(diff <= 0){
typeof callback === 'function' ? callback.call(that) : void(0);
return;
}
diff--;
setTimeout(countdownLoop, 1000);
})();
function zeroPad(num, places) {
var zero = places - num.toString().length + 1;
return Array(+(zero > 0 && zero)).join("0") + num;
}
}
// $('.heading').countDownTimer('2018-04-02 16:00:59', function(){ // on complete})
var hr = 0;
var min = 0;
var sec = 0;
var count = 0;
var flag = false;
function start(){
flag = true;
stopwatch();
}
function stop(){
flag = false;
}
function reset(){
flag = false;
hr = 0;
min = 0;
sec = 0;
count = 0;
document.getElementById("hr").innerHTML = "00";
document.getElementById("min").innerHTML = "00";
document.getElementById("sec").innerHTML = "00";
document.getElementById("count").innerHTML = "00";
}
function stopwatch(){
if(flag == true){
count = count + 1;
setTimeout( 'stopwatch()', 10);
if(count ==100){
count =0;
sec = sec +1;
}
}
if(sec ==60){
min = min +1 ;
sec = 0;
}
if(min == 60){
hr = hr +1 ;
min = 0;
sec = 0;
}
var hrs = hr;
var mins = min;
var secs = sec;
if(hr<10){
hrs ="0" + hr;
}
if(min<10){
mins ="0" + min;
}
if(sec<10){
secs ="0" + sec;
}
document.getElementById("hr").innerHTML = hrs;
document.getElementById("min").innerHTML = mins;
document.getElementById("sec").innerHTML = secs;
document.getElementById("count").innerHTML = count;
}