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Set timer for loop in javascript

I want to set timer-based for loop in JavaScript.
for (var i = 0; i < 20; i++) {
console.log(i)
}
How I can I repeat this loop every second and show the value of i (the counter)?

if you want to control your loops wait time you can combine settimeout with recursion
var i = 0;
function callMe() {
var timetowait = 100;
// some condition and more login
i++;
if(i < 20) {
setTimeout(callMe, timetowait);
}
}
callMe();

I think this is what you are looking for:
var counter = 0;
setInterval( function(){
console.log(counter);
counter++;
},1000);

You can try this approach too:
function loop(start, end, delay, fn) {
if (start > end) return;
function step(){
// callback fn with current iteration and
// recursively calls loop
fn(start);
loop(start + 1, end, delay, fn);
}
setTimeout(step, delay);
}
usage :
loop(1, 20, 1000, console.log)

var i = 0;
function myFunc() {
console.log(i);
i++;
if(i == 20) {
clearInterval(interval);
}
}
var interval = setInterval(myFunc, 1000);
The setInterval() method calls a function or evaluates an expression at -
specified intervals (in milliseconds).
The setInterval() method will continue calling the function until clearInterval() is called, or the window is closed.

jQuery Countdown Each Second

I'm trying to make a jQuery countdown type animation, that once it hits 0 it executes a function. However I'm having problems because I'm unsure how to go about doing this. I thought I'd do a while loop then pause for a second until it hits 0. However it doesn't seem possible to pause a while loop. So I'm wondering what's the best way to do this? Thanks.

countdown takes an HTMLElement to display itself and the number of seconds to count down for
It returns a Promise that resolves when the counter reaches 0
We can use a .then call to apply a function when the count-down has completed
function countdown(elem, s) {
return new Promise(function(resolve) {
function loop(s) {
elem.innerHTML = s
if (s === 0)
resolve(elem)
else
setTimeout(loop, 1000, s - 1)
}
loop(s)
})
}
countdown(document.querySelector('#a'), 3).then(
function(elem) { console.log('done', elem) }
)
countdown(document.querySelector('#b'), 5).then(
function(elem) { console.log('done', elem) }
)
countdown(document.querySelector('#c'), 10).then(
function(elem) { console.log('done', elem) }
)
<p id="a"></p>
<p id="b"></p>
<p id="c"></p>
You should also be aware that setTimeout and setInterval do not guarantee that the milliseconds argument used is 100% accurate …
var last = Date.now()
var interval = setInterval(function() {
var now = Date.now()
var delta = now - last
console.log(delta)
last = now
}, 1000)
setTimeout(clearInterval, 10000, interval)
// 1000
// 1003
// 998
// 1002
// 999
// 1007
// 1001
// ...
If you need a long running timer with high accuracy, I recommend you adapt the solution to use delta-based updates to the clock. If you rely upon setTimeout or setInterval for accuracy, you will be sad.
function countdown(elem, ms) {
return new Promise(function(resolve) {
function loop(ms, last) {
let now = Date.now()
let delta = now - last
if (ms <= 0) {
elem.innerHTML = 0
resolve(elem)
}
else {
elem.innerHTML = (ms/1000).toFixed(3)
setTimeout(loop, 25, ms - delta, now)
}
}
loop(ms, Date.now())
})
}
countdown(document.querySelector('#a'), 3000).then(
function(elem) { console.log('done', elem) }
)
countdown(document.querySelector('#b'), 5000).then(
function(elem) { console.log('done', elem) }
)
countdown(document.querySelector('#c'), 10000).then(
function(elem) { console.log('done', elem) }
)
<p id="a"></p>
<p id="b"></p>
<p id="c"></p>

Code:
var counter = 10;
var yourFunc = function(){}
var interval = setInterval(function(){
counter--;
if(counter <=0){ yourFunc(); clearInterval(interval); }
}, 1000);

I would use a recursive function
var countDown = function(secondsRemaining){
secondsRemaining -= 1;
if(secondsRemaining <= 0){
//execute
} else {
//wait 1 second and call again
setTimeout(function(){
countDown(secondsRemaining);
}, 1000);
}
}
then to initially start countdown (5 seconds)
countDown(5000);

I would use something like the following :
$(document).ready(function(){
var counter=10;
countDown();
function countDown(){
$('#showNumber').text(counter--);
if(counter>=0)
window.setTimeout(countDown,1000)
else
otherFunction();
}
function otherFunction(){
$('#showNumber').text('FINISHED!');
}
});

Try this out. It does not require jQuery.
var count = 5; // Number of times to run 'counter_function'.
// Run 'counter_function' every second (1000ms = 1 second)
var counter = setInterval(function(){
counter_function()
}, 1000);
// The function to run when 'count' hits 0.
var done_function = function() {
console.log('done');
}
// The function to run at each interval.
var counter_function = function() {
console.log('count');
count--;
if(count === 0){
done_function();
clearInterval(counter);
}
}
It will print the word 'count' every second for 5 seconds, and at the last second it will also print 'done'.

Are you looking for something like this OP?
This executes every second. You can use clearInterval() just as I added in the comment section whenever you want it to stop.
var start = 10; // time to countdown from in seconds
var interval = setInterval(
function(){
if (start == 0) {
complete();
clearInterval(interval);
}
$(".update").html("<h4>Countdown "+start+"</h4>");
start--;
}, 1000);
function complete() {
console.log("called the callback, value of start is: "+start);
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class="update">
</div>

Why the timer setTimeout returns the first value "2"

below the code. It should write down to console numbers from 0 to 19. Actually it does. But what is the first number it has print in console?
var i = 0;
var timerId = setInterval(function () {
console.log(i++);
}, 100);
setTimeout(function() {
clearTimeout(timerId)
}, 2100);

Although your code works as expected, it could be that under some conditions you wouldn't print all numbers. It might be better to check the counter value and then clear the interval at that time (timing in javascript is not really that precise as you might hope it to be)
You could try to do it like this though, to make sure that your interval can only run once, and that you don't exceed your max value.
function Counter(start, maxValue, ticks) {
this.value = start || 0;
this.max = maxValue;
this.ticks = ticks;
var interval;
this.stop = function() {
if (!interval) {
return;
}
clearInterval(interval);
console.log('stopped counter');
};
this.increase = function() {
this.value++;
console.log(this.value);
if (this.value >= this.max) {
this.stop();
}
};
this.start = function() {
if (interval) {
return;
}
console.log('starting counter');
interval = setInterval(this.increase.bind(this), this.ticks || 0);
};
}
var counter = new Counter(0, 20, 100);
counter.start();

From setInterval documentation
Calls a function or executes a code snippet repeatedly, with a fixed time delay between each call to that function. Returns an intervalID.

javascript Call function 10 times with 1 second between

How to call a function 10 times like
for(x=0; x<10; x++) callfunction();
but with 1 sec between each call?

function callNTimes(func, num, delay) {
if (!num) return;
func();
setTimeout(function() { callNTimes(func, num - 1, delay); }, delay);
}
callNTimes(callfunction, 10, 1000);
EDIT: The function basically says: make a call of the passed function, then after a bit, do it again 9 more times.

You can use setInterval for repeated execution with intervals and then clearInterval after 10 invocations:
callfunction();
var callCount = 1;
var repeater = setInterval(function () {
if (callCount < 10) {
callfunction();
callCount += 1;
} else {
clearInterval(repeater);
}
}, 1000);
Added: But if you don't know how long it takes your callfunction to execute and the accurate timings between invocation starting points are not important it seems it's better to use setTimeout for reasons mentioned by Paul S and those described in this article.

Another solution
for(var x=0; x<10; x++) window.setTimeout(callfunction, 1000 * x);

You can try to use setInterval and use a variable to count up to 10. Try this:
var number = 1;
function oneSecond () {
if(number <= 10) {
// execute code here..
number++;
}
};
Now use the setInterval:
setInterval(oneSecond, 1000);

Similar to Amadan's answer but with a different style of closure which means you re-use instead of creating new functions
function call(fn, /* ms */ every, /* int */ times) {
var repeater = function () {
fn();
if (--times) window.setTimeout(repeater, every);
};
repeater(); // start loop
}
// use it
var i = 0;
call(function () {console.log(++i);}, 1e3, 10); // 1e3 is 1 second
// 1 to 10 gets logged over 10 seconds
In this example, if you were to set times to either 0 or Infinity, it would run forever.

I don't know if there's a proper name, but I use a repeater:
function Repeater(callback, delay, count) {
var self = this;
this.timer = setTimeout(function() {self.run();},delay);
this.callback = callback;
this.delay = delay;
this.timesLeft = count;
this.lastCalled = new Date().getTime();
}
Repeater.prototype.run = function() {
var self = this;
this.timesLeft--;
this.callback();
this.lastCalled = new Date().getTime();
if( this.timesLeft > 0) {
this.timer = setTimeout(function() {self.run();},this.delay);
}
}
Repeater.prototype.changeDelay = function(newdelay) {
var self = this;
clearTimeout(this.timer);
this.timer = setTimeout(function() {self.run();},
newdelay-new Date().getTime()+lastcalled);
this.delay = newdelay;
}
Repeater.prototype.changeCount = function(newcount) {
var self = this;
if( this.timesLeft == 0) {
this.timer = setTimeout(function() {self.run();},this.delay);
}
this.timesLeft = newcount;
if( this.timesLeft == 0) clearTimeout(this.timer);
}
You can then use it like this:
new Repeater(callfunction, 1000, 10); // 1 second delay, 10 times

const functionCounterTimer = (callCount) => {
if (callCount < 10) {
setTimeout(() => {
++callCount
console.log("Function Call ", callCount);
functionCounterTimer(callCount);
}, 1000);
}
}
functionCounterTimer(0);
The above was my approach to a similar question.

setInterval(function(){},1000);
Calls the function for every second...
You can also use setTimeout for your thing to work.

setTimeout counter not working

This setTimeout function only runs once and then stops. I get no errors so I have no idea why it's happening.
count = 100;
counter = setTimeout('timer()', 100);
$('#reset').click(function() {
count = 100;
counter = setTimeout('timer()', 100);
})
function timer() {
if (count <= 0) {
clearTimeout(counter);
alert('done');
}
$('#counter').html(count);
count -= 1;
}
I tried a few different formulations of the setTimeout function, including setTimeout(timer(),100) and setTimeout(function() { timer() }, 100)

You should be using setInterval() which repeats a function call, not setTimeout(), which does it once. Also, don't use () in function name reference.
var count = 100;
var counter = setInterval('timer', 100);
$('#reset').click(function() {
count = 100;
counter = setInterval('timer', 100);
})
function timer() {
if (count <= 0) {
clearInterval(counter);
alert('done');
}
$('#counter').html(count);
count -= 1;
}

Yes, that's what setTimeout does. It runs the code once.
You want to use the setInterval method to run the code repeatedly.

setTimeout works correctly but it is not what you are looking for. try setInterval instead. setInteval(function, delay)

setTimeout() - executes a function, once, after waiting a specified number of milliseconds.
You probably would like to go for setInterval() which executes a function, over and over again, at specified time intervals.

Not sure what you're trying to achieve, and I don't understand the $('#reset').click (etc) constructs. Are these JQuery?
However, why not use setInterval()? And then clear the interval timer when your condition is met?

var count = 10;
function counter() {
if ( count > 0 )
{
--count;
var t2 = setTimeout( counter, 1000 );
document.querySelector("#demo").innerHTML = count;
}
else
{
clearTimeout(t2);
document.querySelector("#demo").innerHTML = "Done";
}
}
var countdown_timeout = counter();
<p>Count: <b><span id="demo"></span></b></p>