Using setTimeout() it is possible to launch a function at a specified time:
setTimeout(function, 60000);
But what if I would like to launch the function multiple times? Every time a time interval passes, I would like to execute the function (every 60 seconds, let's say).
If you don't care if the code within the timer may take longer than your interval, use setInterval():
setInterval(function, delay)
That fires the function passed in as first parameter over and over.
A better approach is, to use setTimeout along with a self-executing anonymous function:
(function(){
// do some stuff
setTimeout(arguments.callee, 60000);
})();
that guarantees, that the next call is not made before your code was executed. I used arguments.callee in this example as function reference. It's a better way to give the function a name and call that within setTimeout because arguments.callee is deprecated in ecmascript 5.
use the
setInterval(function, 60000);
EDIT : (In case if you want to stop the clock after it is started)
Script section
<script>
var int=self.setInterval(function, 60000);
</script>
and HTML Code
<!-- Stop Button -->
Stop
A better use of jAndy's answer to implement a polling function that polls every interval seconds, and ends after timeout seconds.
function pollFunc(fn, timeout, interval) {
var startTime = (new Date()).getTime();
interval = interval || 1000;
(function p() {
fn();
if (((new Date).getTime() - startTime ) <= timeout) {
setTimeout(p, interval);
}
})();
}
pollFunc(sendHeartBeat, 60000, 1000);
UPDATE
As per the comment, updating it for the ability of the passed function to stop the polling:
function pollFunc(fn, timeout, interval) {
var startTime = (new Date()).getTime();
interval = interval || 1000,
canPoll = true;
(function p() {
canPoll = ((new Date).getTime() - startTime ) <= timeout;
if (!fn() && canPoll) { // ensures the function exucutes
setTimeout(p, interval);
}
})();
}
pollFunc(sendHeartBeat, 60000, 1000);
function sendHeartBeat(params) {
...
...
if (receivedData) {
// no need to execute further
return true; // or false, change the IIFE inside condition accordingly.
}
}
In jQuery you can do like this.
function random_no(){
var ran=Math.random();
jQuery('#random_no_container').html(ran);
}
window.setInterval(function(){
/// call your function here
random_no();
}, 6000); // Change Interval here to test. For eg: 5000 for 5 sec
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="random_no_container">
Hello. Here you can see random numbers after every 6 sec
</div>
setInterval(fn,time)
is the method you're after.
You can simply call setTimeout at the end of the function. This will add it again to the event queue. You can use any kind of logic to vary the delay values. For example,
function multiStep() {
// do some work here
blah_blah_whatever();
var newtime = 60000;
if (!requestStop) {
setTimeout(multiStep, newtime);
}
}
Use window.setInterval(func, time).
A good example where to subscribe a setInterval(), and use a clearInterval() to stop the forever loop:
function myTimer() {
}
var timer = setInterval(myTimer, 5000);
call this line to stop the loop:
clearInterval(timer);
Call a Javascript function every 2 second continuously for 10 second.
var intervalPromise;
$scope.startTimer = function(fn, delay, timeoutTime) {
intervalPromise = $interval(function() {
fn();
var currentTime = new Date().getTime() - $scope.startTime;
if (currentTime > timeoutTime){
$interval.cancel(intervalPromise);
}
}, delay);
};
$scope.startTimer(hello, 2000, 10000);
hello(){
console.log("hello");
}
function random(number) {
return Math.floor(Math.random() * (number+1));
}
setInterval(() => {
const rndCol = 'rgb(' + random(255) + ',' + random(255) + ',' + random(255) + ')';//rgb value (0-255,0-255,0-255)
document.body.style.backgroundColor = rndCol;
}, 1000);
<script src="test.js"></script>
it changes background color in every 1 second (written as 1000 in JS)
// example:
// checkEach(1000, () => {
// if(!canIDoWorkNow()) {
// return true // try again after 1 second
// }
//
// doWork()
// })
export function checkEach(milliseconds, fn) {
const timer = setInterval(
() => {
try {
const retry = fn()
if (retry !== true) {
clearInterval(timer)
}
} catch (e) {
clearInterval(timer)
throw e
}
},
milliseconds
)
}
here we console natural number 0 to ......n (next number print in console every 60 sec.) , using setInterval()
var count = 0;
function abc(){
count ++;
console.log(count);
}
setInterval(abc,60*1000);
I see that it wasn't mentioned here if you need to pass a parameter to your function on repeat setTimeout(myFunc(myVal), 60000); will cause an error of calling function before the previous call is completed.
Therefore, you can pass the parameter like
setTimeout(function () {
myFunc(myVal);
}, 60000)
For more detailed information you can see the JavaScript garden.
Hope it helps somebody.
I favour calling a function that contains a loop function that calls a setTimeout on itself at regular intervals.
function timer(interval = 1000) {
function loop(count = 1) {
console.log(count);
setTimeout(loop, interval, ++count);
}
loop();
}
timer();
There are 2 ways to call-
setInterval(function (){ functionName();}, 60000);
setInterval(functionName, 60000);
above function will call on every 60 seconds.
Related
function tick() {
seconds_lapsed++; // Break point.
}
function countdown() {
while(!stopped || !is_paused()){
setTimeout(tick, 1000); // 1 second.
show_counter();
}
}
Could you tell me why the interpreter doesn't stop at the breakpoint? The while loop works, hava a look at the screenshot.
The while loop is a "busy" loop, i.e. it keeps the JavaScript engine busy, so it will not process anything that is waiting in one of its event/job queues. This means that the user interface does not get updated, no input can be processed, and events produced by setTimeout are not consumed. In this example, tick can only get executed if the currently running code finishes. So the while loop must end first.
You should let tick execute, and only then check the condition:
var stopped = true;
var seconds_lapsed = 0;
document.querySelector("button").addEventListener("click", function() {
stopped = !stopped;
seconds_lapsed = 0;
this.textContent = stopped ? "Start" : "Stop";
if (!stopped) countdown();
});
function show_counter() {
document.querySelector("span").textContent = seconds_lapsed;
}
function is_paused() {
return document.querySelector("input").checked;
}
function tick() {
seconds_lapsed++;
}
function countdown() {
show_counter();
setTimeout(function () {
if (stopped) return; // stop the loop
if (!is_paused()) tick();
countdown(); // <--- this is the "loop"
}, 1000);
}
Seconds elapsed: <span>0</span><br>
<input type="checkbox">Paused<br>
<button>Start</button>
the following example might help you accomplish what you are after. Distinguish between setInterval() and setTimeout()
Basically the docs say:
setTimeout executes a function or specified piece of code once the timer expires.
setInterval repeatedly calls a function or executes a code snippet, with a fixed time delay between each call.
So if you use setInterval you don't need a while loop inside because it is already called "repeatedly"
var counter = $('#counter');
var stopped = false;
var seconds_lapsed=0;
var myInterval;
function tick() {
if(stopped) {
clearInterval(myInterval);
show_counter('FINISHED');
return;
}
show_counter(seconds_lapsed++);
}
function show_counter(message){
counter.html(message);
}
function countdown() {
myInterval = setInterval(tick, 1000);
}
function endCountdown(timeout) {
let timeoutId = setTimeout(function(){
stopped = true;
clearTimeout(timeoutId)
}, timeout);
}
countdown(); // start the countdown
endCountdown(5000); // ends the countdown after 5000 ms => 5sec
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div id="counter">counter</div>
I want repeat this code every 4 seconds, how i can do it with javascript or jquery easly ? Thanks. :)
$.get("request2.php", function(vystup){
if (vystup !== ""){
$("#prompt").html(vystup);
$("#prompt").animate({"top": "+=25px"}, 500).delay(2000).animate({"top": "-=25px"}, 500).delay(500).html("");
}
});
Use setInterval function
setInterval( fn , miliseconds )
From MDC docs:
Summary
Calls a function repeatedly, with a fixed time delay between each call to that function.
Syntax
var intervalID = window.setInterval(func, delay[, param1, param2, ...]);
var intervalID = window.setInterval(code, delay);
where
intervalID is a unique interval ID you can pass to clearInterval().
func is the function you want to be called repeatedly.
code in the alternate syntax, is a string of code you want to be executed repeatedly. (Using this syntax is not recommended for the same reasons as using eval())
delay is the number of milliseconds (thousandths of a second) that the setInterval() function should wait before each call to func. As with setTimeout, there is a minimum delay enforced.
Note that passing additional parameters to the function in the first syntax does not work in Internet Explorer.
Example
// alerts "Hey" every second
setInterval(function() { alert("Hey"); }, 1000);
setInterval(function(){
// your code...
}, 4000);
It's not too hard in javascript.
// declare your variable for the setInterval so that you can clear it later
var myInterval;
// set your interval
myInterval = setInterval(whichFunction,4000);
whichFunction{
// function code goes here
}
// this code clears your interval (myInterval)
window.clearInterval(myInterval);
Hope this helps!
Another possibility is to use setTimeout, but place it along with your code in a function that gets called recursively in the callback to the $.get() request.
This will ensure that the requests are a minimum of 4 seconds apart since the next request will not begin until the previous response was received.
// v--------place your code in a function
function get_request() {
$.get("request2.php", function(vystup){
if (vystup !== ""){
$("#prompt").html(vystup)
.animate({"top": "+=25px"}, 500)
.delay(2000)
.animate({"top": "-=25px"}, 500)
.delay(500)
.html("");
}
setTimeout( get_request, 4000 ); // <-- when you ge a response, call it
// again after a 4 second delay
});
}
get_request(); // <-- start it off
const milliseconds = 4000
setInterval(
() => {
// self executing repeated code below
}, milliseconds);
Call a Javascript function every 2 second continuously for 20 second.
var intervalPromise;
$scope.startTimer = function(fn, delay, timeoutTime) {
intervalPromise = $interval(function() {
fn();
var currentTime = new Date().getTime() - $scope.startTime;
if (currentTime > timeoutTime){
$interval.cancel(intervalPromise);
}
}, delay);
};
$scope.startTimer(hello, 2000, 10000);
hello(){
console.log("hello");
}
My setTimeout() function works, but my clearTimeout() is not working. Even though I have an 'if' statement that's supposed to run the clearTimeout function once my variable 'secs' is less than 0, the timer keeps counting down into negative numbers. When I type my variable name, 'secs' into the console, I get undefined, even though it's defined as a parameter in the function called by my setTimeout. I don't know what I'm doing wrong. Can anyone help, please?
My full code is at https://codepen.io/Rburrage/pen/qBEjXmx;
Here's the JavaScript snippet:
function startTimer(secs, elem) {
t = $(elem);
t.innerHTML = "00:" + secs;
if(secs<0) {
clearTimeout(countDown);
}
secs--;
//recurring function
countDown = setTimeout('startTimer('+secs+',"'+elem+'")', 1000);
}
Add a condition to call recursive function like below.
if (secs < 0) {
secs = secsInput;
}
//recurring function
countDown = setTimeout('startTimer('+secs+',"'+elem+'")', 1000);
For a countdown timer, I would recommend using setInterval and clearInterval instead. setInterval will repeatedly run the callback function for you. It might look like this:
let countdown;
function startTimer(secs, elem) {
countdown = setInterval(function(){
t = $(elem);
t.innerHTML = "00:" + secs;
secs--
if (secs < 0) {
clearInterval(countdown);
}
}, 1000);
}
By the time you call clearTimeout(countDown), countDown refers to the previous timeout, that already timed out. It will not stop the one yet to start. You could just not re set the timeout, like
if(!/*finished*/) setTimeout(startTimer, 1000, secs, elem);
In your case, it's more convenient to use setInterval and clearInterval.
To keep the setTimeout and clearTimeout functions, you should add return in the if statement.
function startTimer(secs, elem) {
t = $(elem);
t.innerHTML = "00:" + secs;
if(secs<0) {
clearTimeout(countDown);
return;
}
secs--;
//recurring function
countDown = setTimeout('startTimer('+secs+',"'+elem+'")', 1000);
}
So there are 4 events in my opinion that will have to be addressed by the timer:
The quiz starts
The quiz ends
The timer runs out
The player answers a question
This can be solved by a function returning an object with some options.
The createTimer can be used to set the parameters for the timer.
Point 1. would be timer.start() --> will start a timer with the parameters
Point 3. can be addressed with the callback that will be called if the timer runs out --> createTimer(5,'display', ()=>{ // your code goes here })
Point 2. can be achieved with --> timer.stop()
Point 4. is needed when the timer needs to be reset without running out timer.reset()
Further on the interval is not in the global scope so you could have multiple timers with different settings and they wouldn't interfere with each other
// function for creating the timer
function createTimer(seconds, cssSelector, callbackOnTimeout) {
// interval the timer is running
let interval;
// the html node where innerText will be set
const display = document.getElementById(cssSelector)
// original seconds passt to createTimer needed for restart
const initSec = seconds
// starting or continuing the interval
function start() {
// setting interval to the active interval
interval = setInterval(() => {
display.innerText = `00:${seconds}`;
--seconds;
if (seconds < 0) {
// calling restart and callback to restart
callbackOnTimeout()
restart()
}
}, 1000);
}
// just stopping but not resetting so calling start will continue the timer
// player takes a break
function stop(){
clearInterval(interval)
}
// opted for a restart and not only a reset since it seemed more appropriate for your problem
function restart(){
clearInterval(interval)
seconds = initSec
start()
}
// returning the object with the functions
return {
start: start,
stop: stop,
restart: restart
}
}
// example for creating a timer
const timer1 = createTimer(5,'display',()=>{
console.log(`you where to slow ohhh...`)
})
// calling the timer
timer1.start()
I have a function that is used to send messages and that is called multiple times in a sec.
But I want to call that function once a sec and delay other calls of that function with another 1-second of the previous call.
So that only that function run in the background and called once in a second, no matters how many times it is called it will delay each call to one second ahead.
For example:
function foo(a) {
console.log(a)
}
foo('one');
foo('two');
foo('three');
in the above example, foo is called three times within a sec but I want to have it called like after the 1 second it should return "one" after 2 seconds it should return 'second' and so on and it should be asynchronous.
How can I do this?
The technology I am using is Javascript.
Thanks
Well this is the first thing I came up with - perhaps it's crude.
var queuedUpCalls = [];
var currentlyProcessingCall = false;
function foo(a) {
if (currentlyProcessingCall) {
queuedUpCalls.push(a);
return;
}
currentlyProcessingCall = true;
setTimeout(function(){
console.log(a);
currentlyProcessingCall = false;
if (queuedUpCalls.length) {
var nextCallArg = queuedUpCalls.shift();
foo(nextCallArg);
}
},1000);
}
foo('one');
foo('two');
foo('three');
For each call, if you're not currently processing a call, just call setTimeout with a delay of 1000ms. If you are processing a call, save off the argument, and when the setTimeout that you kicked off finishes, process it.
Somewhat improved answer using setInterval:
var queuedUpCalls = [];
var timerId;
function foo(a) {
queuedUpCalls.push(a);
if (timerId) {
return;
}
timerId = setInterval(function(){
if (!queuedUpCalls.length) {
clearInterval(timerId);
timerId = null;
return;
}
var nextCallArg = queuedUpCalls.shift();
console.log(nextCallArg);
}, 1000);
}
foo('one');
foo('two');
foo('three');
Here is a simple queue system, it basically just pushes the functions onto an array, and then splice's them off every second.
const queue = [];
setInterval(function () {
if (!queue.length) return;
const f = queue[0];
queue.splice(0, 1);
f();
}, 1000);
function foo(a) {
queue.push(function () {
console.log(a)
});
}
foo('one');
foo('two');
foo('three');
you could use this to run the main code first and then run some more code a little later.
function firstfunction() {
alert('I am ran first');
setTimeout(function(){ alert('I am ran 3 seconds later') }, 3000);
}
<button onclick="firstfunction();">click me</button>
function foo(a)
{
if (typeof foo.last == 'undefined')
foo.last = Date.now();
var now = Date.now();
if (now - 1000 > foo.time)
foo.last = now;
setTimeout(function()
{
console.log(a);
}, (foo.last += 1000) - now);
}
This will queue each console.log call with intervals of 1 second, the first call will also be delayed by 1 second.
You could do this:
function foo() {
console.log(“ran”);
}
setInterval(foo, 1000);
In the last line, writing foo() without parenthesis is intentional. The line doesn’t work if you add parentheses.
I want repeat this code every 4 seconds, how i can do it with javascript or jquery easly ? Thanks. :)
$.get("request2.php", function(vystup){
if (vystup !== ""){
$("#prompt").html(vystup);
$("#prompt").animate({"top": "+=25px"}, 500).delay(2000).animate({"top": "-=25px"}, 500).delay(500).html("");
}
});
Use setInterval function
setInterval( fn , miliseconds )
From MDC docs:
Summary
Calls a function repeatedly, with a fixed time delay between each call to that function.
Syntax
var intervalID = window.setInterval(func, delay[, param1, param2, ...]);
var intervalID = window.setInterval(code, delay);
where
intervalID is a unique interval ID you can pass to clearInterval().
func is the function you want to be called repeatedly.
code in the alternate syntax, is a string of code you want to be executed repeatedly. (Using this syntax is not recommended for the same reasons as using eval())
delay is the number of milliseconds (thousandths of a second) that the setInterval() function should wait before each call to func. As with setTimeout, there is a minimum delay enforced.
Note that passing additional parameters to the function in the first syntax does not work in Internet Explorer.
Example
// alerts "Hey" every second
setInterval(function() { alert("Hey"); }, 1000);
setInterval(function(){
// your code...
}, 4000);
It's not too hard in javascript.
// declare your variable for the setInterval so that you can clear it later
var myInterval;
// set your interval
myInterval = setInterval(whichFunction,4000);
whichFunction{
// function code goes here
}
// this code clears your interval (myInterval)
window.clearInterval(myInterval);
Hope this helps!
Another possibility is to use setTimeout, but place it along with your code in a function that gets called recursively in the callback to the $.get() request.
This will ensure that the requests are a minimum of 4 seconds apart since the next request will not begin until the previous response was received.
// v--------place your code in a function
function get_request() {
$.get("request2.php", function(vystup){
if (vystup !== ""){
$("#prompt").html(vystup)
.animate({"top": "+=25px"}, 500)
.delay(2000)
.animate({"top": "-=25px"}, 500)
.delay(500)
.html("");
}
setTimeout( get_request, 4000 ); // <-- when you ge a response, call it
// again after a 4 second delay
});
}
get_request(); // <-- start it off
const milliseconds = 4000
setInterval(
() => {
// self executing repeated code below
}, milliseconds);
Call a Javascript function every 2 second continuously for 20 second.
var intervalPromise;
$scope.startTimer = function(fn, delay, timeoutTime) {
intervalPromise = $interval(function() {
fn();
var currentTime = new Date().getTime() - $scope.startTime;
if (currentTime > timeoutTime){
$interval.cancel(intervalPromise);
}
}, delay);
};
$scope.startTimer(hello, 2000, 10000);
hello(){
console.log("hello");
}