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Javascrip count down timer: prevent reseting on page reload

I have a minute timer which counts from 15 to 0. I don't want to reset (= restart) the timer on page reload. but I can't figure out how to prevent the timer from resetting on a page reload. I'm using javascript with php. I have tried to add the timer time on load to php session but that didn't work for me. any suggestions? thank you :)
function startTimer() {
setTimeout('timer()', 60);
}
var continueMins = localStorage.getItem("continueMins");
var continueSecs = localStorage.getItem("continueSecs");
if (continueMins == 'true') {
mins = continueMins;
} else {
mins = 15;
}
if (continueSecs == 'true') {
secs = continueSecs;
} else {
secs = mins * 60;
}
function timer() {
if (document.getElementById) {
minutes = document.getElementById("minutes");
seconds = document.getElementById("seconds");
progressBar = document.getElementById("progressBar");
timerContainer = document.getElementById("timer-container");
expired = document.getElementById("expired");
btcAmount = document.getElementById("btcAmount");
btcAddress = document.getElementById("btcAddress");
window.onbeforeunload = function() {
localStorage.setItem("continueMins", getMinutes());
localStorage.setItem("continueSecs", getSeconds());
}
var totalSeconds = 15 * 60, remainingSeconds = getMinutes() * 60 + getSeconds();
progressBar.style.width = (remainingSeconds * 100 / totalSeconds) + "%";
minutes.innerHTML = getMinutes() < 10 ? "0" + getMinutes() : getMinutes();
seconds.innerHTML = getSeconds() < 10 ? "0" + getSeconds() : getSeconds();
if (mins < 1) {
minutes.classList.add("text-danger");
seconds.classList.add("text-danger");
}
if (mins < 0) {
expired.style.display = 'block';
timerContainer.style.display = 'none';
btcAmount.text = 'Expired';
btcAddress.text = 'Payment Window Expired';
localStorage.removeItem("continueMins");
localStorage.removeItem("continueSecs");
} else {
secs--;
setTimeout('timer()', 1000);
}
}
}
function getMinutes() {
mins = Math.floor(secs / 60);
return mins;
}
function getSeconds() {
return secs - Math.round(mins * 60);
}
startTimer();
<p class="font-18 font-500"><span id="minutes"></span> : <span id="seconds"></span></p>

You could use the localStorage (sessionStorage is also an option but more prone to restart your timer if the user e.g. reconnects in a new tab or restarts the browser)
How to do it to be on the save side (crashes, unexpected bahaviour e.g.you should update the elapsed time in your local storage from time to time. The "normal" situations are handled by checking for the respective event:
var aTimer, bool;
window.onbeforeunload = function (e) {
if (bool) return;
aTimer = setTimeout(function () {
bool = true;
localStorage.setItem("resetTimer", "false");
localStorage.setItem("currentTimer", MY_TIMER_VAR);
localStorage.setItem("sessionDate", MY_NEW_SESSION_VAR);
}, 500);
return ;
};
EDIT If you want that an elapsed timer is valid for lets say 24 hours you have also to place MY_NEW_SESSION_VAR which is a Date.now() converted in hours when reloading you check against TODAY_DATETIME_IN_HOURS which is a Date.now() converted in hours (This was my use case, if you do not need it just leave it out)
The keys and the values are always strings (note that, as with objects, integer keys will be automatically converted to strings).
When starting your program (loading js) you should check for the vars with:
var resetTimer = localStorage.getItem("resetTimer");
var sessionDate = localStorage.getItem("sessionDate");
if (resetTimer == "true" || sessionDate > (TODAY_DATETIME_IN_HOURS - 24) ){ // start timer }
To delete a single item
localStorage.removeItem("sessionDate");
If you want to use sessionStorage just replace localStorage with sessionStorage
EDIT full code for the OP tested and working as asked
var countDownTarget;
if (document.readyState!="loading") docReady();
/* Modern browsers */
else document.addEventListener("DOMContentLoaded", docReady);
function docReady() {
countDownTarget = parseInt(localStorage.getItem("countDownTarget"));
console.debug("Initvalue: " + countDownTarget);
if (isNaN(countDownTarget) == true || countDownTarget == "" || countDownTarget <= 0){ // If not defined
countDownTarget = new Date().getTime() + 15 * 60 * 1000;
console.debug("is NaN sInitvalue: " + countDownTarget);
//Update the count down every 1 second
setInterval(countDown, 1000);
} else {
console.debug("else Initvalue: " + countDownTarget);
setInterval(countDown, 1000);
}
}
window.onbeforeunload = function() {
localStorage.setItem("countDownTarget", countDownTarget);
};
// Functions you call
function countDown(){
var now = new Date().getTime();
//console.debug("now " + now);
var distance = countDownTarget - now;
console.debug("distance " + distance);
var mins = distance < 0 ? 0 : Math.floor((distance % (1000 * 60 * 60)) / (1000 * 60));
var secs = distance < 0 ? 0 : Math.floor((distance % (1000 * 60)) / 1000);
/** Add a zero in front of numbers<10 */
mins = prependZero(mins);
secs = prependZero(secs);
// Output the results
document.getElementById("minutes").innerHTML = mins;
document.getElementById("seconds").innerHTML = secs;
if (distance <= 0) {
// clearInterval(x);
localStorage.removeItem("countDownTarget");
clearInterval(countDown);
}
}
function prependZero(i){
if (i < 10) {
i = "0" + i;
}
return i;
}
Copy between your script tags or load as *.js file

Change hourly jquery timer to daily

Hi everybody I’ve tried (and failed) to change this simple jquery code to countdown 24 hours instead of the current 1 hour. I have a function called getMinutesUntilNextHour() that should calculate and display the 24 hour countdown:
function getMinutesUntilNextHour() {
var now = new Date();
var mins = now.getMinutes();
var secs = now.getSeconds();
var cur_mins = 60 - mins;
var cur_secs = 60 - secs;
if (cur_secs == 60) {
cur_mins = cur_mins;
cur_secs = 0;
} else {
cur_mins = cur_mins - 1;
}
if(secs > 50){
var response = (cur_mins) + ":0" + (cur_secs);
} else if(cur_secs == 0) {
var response = (cur_mins) + ":00";
} else {
var response = (cur_mins) + ":" + (cur_secs);
}
jQuery('#time_till_hour').text(function(){
return response;
});
setTimeout(getMinutesUntilNextHour, 1000);
}
getMinutesUntilNextHour();
I added now.getHours() then cur_hours = 24 - hours but it doesn’t display correctly. Should I add something to if current hours = 0 section?
Thanks in advance for any help you may be able to offer

Perhaps you could adjust and simplify your getMinutesUntilNextHour() function in the following way:
function getMinutesUntilNextHour() {
var now = new Date();
var hours = now.getHours();
var mins = now.getMinutes();
var secs = now.getSeconds();
// Compute time remaining per unit
var cur_hours = 23 - hours;
var cur_mins = 60 - mins;
var cur_secs = 60 - secs;
// Correct zero padding of hours if needed
if(cur_hours < 10) {
cur_hours = '0' + cur_hours;
}
// Correct zero padding of minutes if needed
if(cur_mins < 10) {
cur_mins = '0' + cur_mins;
}
// Correct zero padding of seconds if needed
if(cur_secs < 10) {
cur_secs = '0' + cur_secs;
}
// Format the countdown string
var response = cur_hours + ':' + cur_mins + ':' + cur_secs;
jQuery('#time_till_hour').text(response);
setTimeout(getMinutesUntilNextHour, 1000);
}
getMinutesUntilNextHour();
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.0.0/jquery.min.js"></script>
<div id="time_till_hour">
</div>
Hope that helps!

Javascript Count Up Timer

I am trying to make a javascript timer that when initiated, starts counting up. The timer is just a visual reference from when a start button is clicked to when the end button is clicked.
I found a plugin online which works perfectly for counting down but I am trying to modify it to count up.
I hard coded a date way in the future. I am now trying to get the timer to start counting up to that date. This will be reset every time the start button is clicked.
This is the function I am working with. it works perfectly to count down but I cant figure out how to reverse it.
I thought it was something with how the differece was calculated but I believe it actually happens in the //calculate dates section.
Is there an easy way to reverse this math and have it count up instead?
Fiddle: http://jsfiddle.net/xzjoxehj/
var currentDate = function () {
// get client's current date
var date = new Date();
// turn date to utc
var utc = date.getTime() + (date.getTimezoneOffset() * 60000);
// set new Date object
var new_date = new Date(utc + (3600000*settings.offset))
return new_date;
};
function countdown () {
var target_date = new Date('12/31/2020 12:00:00'), // Count up to this date
current_date = currentDate(); // get fixed current date
// difference of dates
var difference = current_date - target_date;
// if difference is negative than it's pass the target date
if (difference > 0) {
// stop timer
clearInterval(interval);
if (callback && typeof callback === 'function') callback();
return;
}
// basic math variables
var _second = 1000,
_minute = _second * 60,
_hour = _minute * 60,
_day = _hour * 24;
// calculate dates
var days = Math.floor(difference / _day),
hours = Math.floor((difference % _day) / _hour),
minutes = Math.floor((difference % _hour) / _minute),
seconds = Math.floor((difference % _minute) / _second);
// fix dates so that it will show two digets
days = (String(days).length >= 2) ? days : '0' + days;
hours = (String(hours).length >= 2) ? hours : '0' + hours;
minutes = (String(minutes).length >= 2) ? minutes : '0' + minutes;
seconds = (String(seconds).length >= 2) ? seconds : '0' + seconds;
// set to DOM
//
};
// start
var interval = setInterval(countdown, 1000);
};

JSFiddle
var original_date = currentDate();
var target_date = new Date('12/31/2020 12:00:00'); // Count up to this date
var interval;
function resetCountdown() {
original_date = currentDate();
}
function stopCountdown() {
clearInterval(interval);
}
function countdown () {
var current_date = currentDate(); // get fixed current date
// difference of dates
var difference = current_date - original_date;
if (current_date >= target_date) {
// stop timer
clearInterval(interval);
if (callback && typeof callback === 'function') callback();
return;
}
// basic math variables
var _second = 1000,
_minute = _second * 60,
_hour = _minute * 60,
_day = _hour * 24;
// calculate dates
var days = Math.floor(difference / _day),
hours = Math.floor((difference % _day) / _hour),
minutes = Math.floor((difference % _hour) / _minute),
seconds = Math.floor((difference % _minute) / _second);
// fix dates so that it will show two digets
days = (String(days).length >= 2) ? days : '0' + days;
hours = (String(hours).length >= 2) ? hours : '0' + hours;
minutes = (String(minutes).length >= 2) ? minutes : '0' + minutes;
seconds = (String(seconds).length >= 2) ? seconds : '0' + seconds;
// set to DOM
//
};
// start
interval = setInterval(countdown, 1000);
};

This OP already has an answer but that has issue with timezone , so this answer.
DownVoters care to comment.
Try this. Fiddle
var TargetDate = new Date('2015', '08', '04', 11, 11, 30) // second parameter is month and it is from from 0-11
$('#spanTargetDate').text(TargetDate);
$('#spanStartDate').text(new Date());
var Sec = 0,
Min = 0,
Hour = 0,
Days = 0;
var counter = setInterval(function () {
var CurrentDate = new Date()
$('#spanCurrentDate').text(CurrentDate);
var Diff = TargetDate - CurrentDate;
if (Diff < 0) {
clearInterval(counter);
$('#timer').text('Target Time Expired. test in fiddle')
} else {
++Sec;
if (Sec == 59) {
++Min;
Sec = 0;
}
if (Min == 59) {
++Hour;
Min = 0;
}
if (Hour == 24) {
++Days;
Hour = 0;
}
if (Sec <= Diff) $('#timer').text(pad(Days) + " : " + pad(Hour) + " : " + pad(Min) + " : " + pad(Sec));
}
}, 1000);
function pad(number) {
if (number <= 9) {
number = ("0" + number).slice(-4);
}
return number;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
Target Time - <span id="spanTargetDate"></span>
<br/>
<br/>Start Time - <span id="spanStartDate"></span>
<br/>
<br/>Current Time - <span id="spanCurrentDate"></span>
<br/>
<br/>Timer (DD:HH:MM:SS) - <span id="timer"></span>
<br/>
<br/>

Find elapsed time in javascript

I'm new to JavaScript and I'm trying to write a code which calculates the time elapsed from the time a user logged in to the current time.
Here is my code:-
function markPresent() {
window.markDate = new Date();
$(document).ready(function() {
$("div.absent").toggleClass("present");
});
updateClock();
}
function updateClock() {
var markMinutes = markDate.getMinutes();
var markSeconds = markDate.getSeconds();
var currDate = new Date();
var currMinutes = currDate.getMinutes();
var currSeconds = currDate.getSeconds();
var minutes = currMinutes - markMinutes;
if(minutes < 0) { minutes += 60; }
var seconds = currSeconds - markSeconds;
if(seconds < 0) { seconds += 60; }
if(minutes < 10) { minutes = "0" + minutes; }
if(seconds < 10) { seconds = "0" + seconds; }
var hours = 0;
if(minutes == 59 && seconds == 59) { hours++; }
if(hours < 10) { hours = "0" + hours; }
var timeElapsed = hours+':'+minutes+':'+seconds;
document.getElementById("timer").innerHTML = timeElapsed;
setTimeout(function() {updateClock()}, 1000);
}
The output is correct upto 00:59:59 but after that that O/P is:
00:59:59
01:59:59
01:59:00
01:59:01
.
.
.
.
01:59:59
01:00:00
How can I solve this and is there a more efficient way I can do this?
Thank you.

No offence, but this is massively over-enginered. Simply store the start time when the script first runs, then subtract that from the current time every time your timer fires.
There are plenty of tutorials on converting ms into a readable timestamp, so that doesn't need to be covered here.
var start = Date.now();
setInterval(function() {
document.getElementById('difference').innerHTML = Date.now() - start;
// the difference will be in ms
}, 1000);
<div id="difference"></div>

There's too much going on here.
An easier way would just be to compare markDate to the current date each time and reformat.
See Demo: http://jsfiddle.net/7e4psrzu/
function markPresent() {
window.markDate = new Date();
$(document).ready(function() {
$("div.absent").toggleClass("present");
});
updateClock();
}
function updateClock() {
var currDate = new Date();
var diff = currDate - markDate;
document.getElementById("timer").innerHTML = format(diff/1000);
setTimeout(function() {updateClock()}, 1000);
}
function format(seconds)
{
var numhours = parseInt(Math.floor(((seconds % 31536000) % 86400) / 3600),10);
var numminutes = parseInt(Math.floor((((seconds % 31536000) % 86400) % 3600) / 60),10);
var numseconds = parseInt((((seconds % 31536000) % 86400) % 3600) % 60,10);
return ((numhours<10) ? "0" + numhours : numhours)
+ ":" + ((numminutes<10) ? "0" + numminutes : numminutes)
+ ":" + ((numseconds<10) ? "0" + numseconds : numseconds);
}
markPresent();
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.0/jquery.min.js"></script>
<div id="timer"></div>

Here is a solution I just made for my use case. I find it is quite readable. The basic premise is to simply subtract the timestamp from the current timestamp, and then divide it by the correct units:
const showElapsedTime = (timestamp) => {
if (typeof timestamp !== 'number') return 'NaN'
const SECOND = 1000
const MINUTE = 1000 * 60
const HOUR = 1000 * 60 * 60
const DAY = 1000 * 60 * 60 * 24
const MONTH = 1000 * 60 * 60 * 24 * 30
const YEAR = 1000 * 60 * 60 * 24 * 30 * 12
// const elapsed = ((new Date()).valueOf() - timestamp)
const elapsed = 1541309742360 - timestamp
if (elapsed <= MINUTE) return `${Math.round(elapsed / SECOND)}s`
if (elapsed <= HOUR) return `${Math.round(elapsed / MINUTE)}m`
if (elapsed <= DAY) return `${Math.round(elapsed / HOUR)}h`
if (elapsed <= MONTH) return `${Math.round(elapsed / DAY)}d`
if (elapsed <= YEAR) return `${Math.round(elapsed / MONTH)}mo`
return `${Math.round(elapsed / YEAR)}y`
}
const createdAt = 1541301301000
console.log(showElapsedTime(createdAt + 5000000))
console.log(showElapsedTime(createdAt))
console.log(showElapsedTime(createdAt - 500000000))
For example, if 3000 milliseconds elapsed, then 3000 is greater than SECONDS (1000) but less than MINUTES (60,000), so this function will divide 3000 by 1000 and return 3s for 3 seconds elapsed.
If you need timestamps in seconds instead of milliseconds, change all instances of 1000 to 1 (which effectively multiplies everything by 1000 to go from milliseconds to seconds (ie: because 1000ms per 1s).
Here are the scaling units in more DRY form:
const SECOND = 1000
const MINUTE = SECOND * 60
const HOUR = MINUTE * 60
const DAY = HOUR * 24
const MONTH = DAY * 30
const YEAR = MONTH * 12

We can also use console.time() and console.timeEnd() method for the same thing.
Syntax:
console.time(label);
console.timeEnd(label);
Label:
The name to give the new timer. This will identify the timer; use the same name when calling console.timeEnd() to stop the timer and get the time output to the console.
let promise = new Promise((resolve, reject) => setTimeout(resolve, 400, 'resolved'));
// Start Timer
console.time('x');
promise.then((result) => {
console.log(result);
// End Timer
console.timeEnd('x');
});

You can simply use performance.now()
Example:
start = performance.now();
elapsedTime = performance.now() - start;

var hours = 0;
if(minutes == 59 && seconds == 59)
{
hours = hours + 1;
minutes = '00';
seconds == '00';
}

I would use the getTime() method, subtract the time and then convert the result into hh:mm:ss.mmm format.

I know this is kindda old question but I'd like to apport my own solution in case anyone would like to have a JS encapsulated plugin for this. Ideally I would have: start, pause, resume, stop, reset methods. Giving the following code all of the mentioned can easily be added.
(function(w){
var timeStart,
timeEnd,
started = false,
startTimer = function (){
this.timeStart = new Date();
this.started = true;
},
getPartial = function (end) {
if (!this.started)
return 0;
else {
if (end) this.started = false;
this.timeEnd = new Date();
return (this.timeEnd - this.timeStart) / 1000;
}
},
stopTime = function () {
if (!this.started)
return 0;
else {
return this.getPartial(true);
}
},
restartTimer = function(){
this.timeStart = new Date();
};
w.Timer = {
start : startTimer,
getPartial : getPartial,
stopTime : stopTime,
restart : restartTimer
};
})(this);
Start
Partial
Stop
Restart

What I found useful is a 'port' of a C++ construct (albeit often in C++ I left show implicitly called by destructor):
var trace = console.log
function elapsed(op) {
this.op = op
this.t0 = Date.now()
}
elapsed.prototype.show = function() {
trace.apply(null, [this.op, 'msec', Date.now() - this.t0, ':'].concat(Array.from(arguments)))
}
to be used - for instance:
function debug_counters() {
const e = new elapsed('debug_counters')
const to_show = visibleProducts().length
e.show('to_show', to_show)
}

Running a Javascript Clock at 4x Speed [duplicate]

This question already has answers here:
Closed 10 years ago.
Possible Duplicate:
Javascript to run the Clock (date and time) 4 times speeder
I'm trying to make a clock that starts at a time value (hh:mm:ss) that I've supplied, and runs at 4x speed (for the server time of an online game that runs 4x actual time). I've modified a free clock that I found online to do this, but it only works for every other minute (try the code below to see exactly what I mean if that doesn't make sense).
var customClock = (function () {
var timeDiff;
var timeout;
function addZ(n) {
return (n < 10 ? '0' : '') + n;
}
function formatTime(d) {
t1 = d.getHours();
t2 = d.getMinutes();
t3 = d.getSeconds() * 4;
if (t3 > 59) {
t3 = t3 - 60;
t2 = t2 + 1;
}
if (t2 > 59) {
t2 = t2 - 60;
t1 = t1 + 1;
}
if (t1 > 23) {
t1 = 0;
}
return addZ(t1) + ':' + addZ(t2) + ':' + addZ(t3);
}
return function (s) {
var now = new Date();
var then;
var lag = 1015 - now.getMilliseconds();
if (s) {
s = s.split(':');
then = new Date(now);
then.setHours(+s[0], +s[1], +s[2], 0);
timeDiff = now - then;
}
now = new Date(now - timeDiff);
document.getElementById('clock').innerHTML = formatTime(now);
timeout = setTimeout(customClock, lag);
}
}());
window.onload = function () {
customClock('00:00:00');
};
Any idea why this is happening? I'm pretty new to Javascript and this is definitely a little hack-ey. Thanks

i take the orginal time and substract it from the current then multiply it by 4 and add it to the orginal time. I think that should take care or the sync problem.
(function(){
var startTime = new Date(1987,08,13).valueOf() //save the date 13. august 1987
, interval = setInterval(function() {
var diff = Date.now() - startTime
//multiply the diff by 4 and add to original time
var time = new Date(startTime + (diff*4))
console.log(time.toLocaleTimeString())
}, 1000)
}())
How to use with a custom date (use the Date object)
Date(year, month, day, hours, minutes, seconds, milliseconds)

var lag = 1015 - now.getMilliseconds(); is attempting to "run this again a smidge (15 ms) after the next clock tick". Make this value smaller (divide by 4?), and this code will run more frequently.
Next up, get it to show 4x the current clock duration. Similar problem: multiply now's details by 4 either inside or outside formatTime()

I would first create a Clock constructor as follows:
function Clock(id) {
var clock = this;
var timeout;
var time;
this.hours = 0;
this.minutes = 0;
this.seconds = 0;
this.stop = stop;
this.start = start;
var element = document.getElementById(id);
function stop() {
clearTimeout(timeout);
}
function start() {
timeout = setTimeout(tick, 0);
time = Date.now();
}
function tick() {
time += 1000;
timeout = setTimeout(tick, time - Date.now());
display();
update();
}
function display() {
var hours = clock.hours;
var minutes = clock.minutes;
var seconds = clock.seconds;
hours = hours < 10 ? "0" + hours : "" + hours;
minutes = minutes < 10 ? "0" + minutes : "" + minutes;
seconds = seconds < 10 ? "0" + seconds : "" + seconds;
element.innerHTML = hours + ":" + minutes + ":" + seconds;
}
function update() {
var seconds = clock.seconds += 4;
if (seconds === 60) {
clock.seconds = 0;
var minutes = ++clock.minutes;
if (minutes === 60) {
clock.minutes = 0;
var hours = ++clock.hours;
if (hours === 24) clock.hours = 0;
}
}
}
}
Then you can create a clock and start it like this:
var clock = new Clock("clock");
clock.start();
Here's a demo: http://jsfiddle.net/Nt5XN/