Develop Reference

The event .click fires multiple times

On the page there is a link with id get-more-posts, by clicking on which articles are loaded. Initially, it is outside the screen. The task is to scroll the screen to this link by clicking on it. The code below does what you need. But the event is called many times. Only need one click when I get to this element scrolling.
p.s. sorry for my bad english
$(window).on("scroll", function() {
if((($(window).scrollTop()+$(window).height())+250)>=$(document).height()){
$('#get-more-posts').click();
}
});

Try use removeEventListener or use variable with flag, just event scroll detached more at once

You can set up throttling by checking if you are already running the callback. One way is with a setTimeout function, like below:
var throttled = null;
$(window).on("scroll", function() {
if(!throttled){
throttled = setTimeout(function(){
if((($(window).scrollTop()+$(window).height())+250)>=$(document).height()){
$('#get-more-posts').click();
throttled = null;
}
}.bind(window), 50);
}
}.bind(window));
Here's an ES6 version that might resolve the scoping issues I mentioned:
let throttled = null;
$(window).on("scroll", () => {
if(!throttled){
throttled = setTimeout(() => {
if((($(window).scrollTop()+$(window).height())+250)>=$(document).height()){
$('#get-more-posts').click();
throttled = null;
}
}, 50);
}
});
The last argument of setTimeout is the delay before running. I chose 50 arbitrarily but you can experiment to see what works best.

I don't know how true it is, but it works. After the event (click), delete the element id, and then add it again, so the click is performed once. Scroll the page to the desired item, click again, delete the id and add it again. It works. Can someone come in handy.
window.addEventListener('scroll', throttle(callback, 50));
function throttle(fn, wait) {
var time = Date.now();
return function() {
if ((time + wait - Date.now()) < 0) {
fn();
time = Date.now();
}
}
}
function callback() {
var target = document.getElementById('get-more-posts');
if((($(window).scrollTop()+$(window).height())+650)>=$(document).height()){
$('#get-more-posts').click();
$("#get-more-posts").removeAttr("id");
//$(".get-more-posts").attr("id='get-more-posts'");
};
}
window.removeEventListener('scroll', throttle(callback, 50));

How can I depend on the interval that I just cleared in jquery?

It's a follow up to this question - https://stackoverflow.com/a/33430608/3766930
Basically I have a text area and when user starts typing in sth, the counter starts going down from 3 to 0. when it reaches 0 it gets disabled.
Now I want to add a feature of starting over - when user clicks the link start over, text area goes enabled again and user has 3 seconds (again) to perform the input.
I modified the jquery script:
$('#textArea').on('input propertychange', display30Seconds);
var interval;
function display30Seconds() {
var validTime = 3000;
if (!interval)
interval = setInterval(function () {
$('#counter').html(validTime / 1000);
validTime = validTime - 1000;
if (validTime < 0) {
clearInterval(interval);
alert('Time Up!');
$('#textArea').prop('disabled', true);
$('#counter').html('start over');
$('#counterIsDone').on('click', function(){
$('#textArea').prop('disabled', false);
display30Seconds();
});
}
}, 1000);
}
but I see that I cannot call the method display30Seconds(); again. Or rather I can, but the interval is not set again. How can I fix it?
Seems like I'm not entering the code inside
if (!interval)
because the interval is not visible any more after clearing it (?). So I thought about moving the var interval; into the body of the method function display30Seconds() {, but that doesn't bring the expected effect. Is there a way of fixing it?
Here is my updated fiddle: http://jsfiddle.net/jf4ea4nx/3/

Set interval=null after the clearInterval() call.
What seems to confuse you is the semantics of clearInterval(interval). As Patrick Evans points out in his comment, it will not set interval to a value that evaluates to false in a condition.
To make it completely clear you could use a boolean variable such as countdownRunning in addition to the interval variable to keep track of whether the countdown is active or not.

Try this:
$('#textArea').on('input propertychange', display30Seconds);
var interval=false;
function display30Seconds() {
var validTime = 3000;
if (!interval)
interval = setInterval(function () {
$('#counter').html(validTime / 1000);
validTime = validTime - 1000;
if (validTime < 0) {
clearInterval(interval);
alert('Time Up!');
$('#textArea').prop('disabled', true);
$('#counter').html('start over');
$(document).on('click','#counterIsDone', function(){
$('#textArea').prop('disabled', false);
display30Seconds();
});
interval=false;
}
}, 1000);
}

You can improve your code by using a conditional recursive call to to your iterative function instead - each call has a one second delay, which makes it slightly more intuitive to use (think of each call as one tick):
var seconds = 3;
$('#textArea').on('input propertychange', setTimeout(timeout.bind(null, seconds), 1000));
function timeout (iterations) {
$('#counter').html(iterations);
if (iterations === 0) {
alert('Time Up!');
$('#textArea').prop('disabled', true);
$('#counter').html('start over');
$('#counterIsDone').on('click', function(){
$('#textArea').prop('disabled', false);
timeout(seconds);
});
}
else {
setTimeout(timeout.bind(null, --iterations), 1000);
}
}
The bind function simply binds the arguments of the bind function to the arguments of the timeout call - the first argument to the bind function declares its this scope; but don't worry about that too much.
You can modify the duration of the timer by changing the seconds var. Hope this helps :)

How to Monitor user idle in an applet inside a html using java script [duplicate]

Is it possible to detect "idle" time in JavaScript?
My primary use case probably would be to pre-fetch or preload content.
I define idle time as a period of user inactivity or without any CPU usage

Here is a simple script using jQuery that handles mousemove and keypress events.
If the time expires, the page reloads.
<script type="text/javascript">
var idleTime = 0;
$(document).ready(function () {
// Increment the idle time counter every minute.
var idleInterval = setInterval(timerIncrement, 60000); // 1 minute
// Zero the idle timer on mouse movement.
$(this).mousemove(function (e) {
idleTime = 0;
});
$(this).keypress(function (e) {
idleTime = 0;
});
});
function timerIncrement() {
idleTime = idleTime + 1;
if (idleTime > 19) { // 20 minutes
window.location.reload();
}
}
</script>

With vanilla JavaScript:
var inactivityTime = function () {
var time;
window.onload = resetTimer;
// DOM Events
document.onmousemove = resetTimer;
document.onkeydown = resetTimer;
function logout() {
alert("You are now logged out.")
//location.href = 'logout.html'
}
function resetTimer() {
clearTimeout(time);
time = setTimeout(logout, 3000)
// 1000 milliseconds = 1 second
}
};
And initialise the function where you need it (for example: onPageLoad).
window.onload = function() {
inactivityTime();
}
You can add more DOM events if you need to. Most used are:
document.onload = resetTimer;
document.onmousemove = resetTimer;
document.onmousedown = resetTimer; // touchscreen presses
document.ontouchstart = resetTimer;
document.onclick = resetTimer; // touchpad clicks
document.onkeydown = resetTimer; // onkeypress is deprectaed
document.addEventListener('scroll', resetTimer, true); // improved; see comments
Or register desired events using an array
window.addEventListener('load', resetTimer, true);
var events = ['mousedown', 'mousemove', 'keypress', 'scroll', 'touchstart'];
events.forEach(function(name) {
document.addEventListener(name, resetTimer, true);
});
DOM Events list: http://www.w3schools.com/jsref/dom_obj_event.asp
Remember to use window, or document according your needs. Here you can see the differences between them: What is the difference between window, screen, and document in JavaScript?
Code Updated with #frank-conijn and #daxchen improve: window.onscroll will not fire if scrolling is inside a scrollable element, because scroll events don't bubble. In window.addEventListener('scroll', resetTimer, true), the third argument tells the listener to catch the event during the capture phase instead of the bubble phase.

Improving on Equiman's (original) answer:
function idleLogout() {
var t;
window.onload = resetTimer;
window.onmousemove = resetTimer;
window.onmousedown = resetTimer; // catches touchscreen presses as well
window.ontouchstart = resetTimer; // catches touchscreen swipes as well
window.ontouchmove = resetTimer; // required by some devices
window.onclick = resetTimer; // catches touchpad clicks as well
window.onkeydown = resetTimer;
window.addEventListener('scroll', resetTimer, true); // improved; see comments
function yourFunction() {
// your function for too long inactivity goes here
// e.g. window.location.href = 'logout.php';
}
function resetTimer() {
clearTimeout(t);
t = setTimeout(yourFunction, 10000); // time is in milliseconds
}
}
idleLogout();
Apart from the improvements regarding activity detection, and the change from document to window, this script actually calls the function, rather than letting it sit idle by.
It doesn't catch zero CPU usage directly, but that is impossible, because executing a function causes CPU usage. And user inactivity eventually leads to zero CPU usage, so indirectly it does catch zero CPU usage.

I have created a small library that does this:
https://github.com/shawnmclean/Idle.js
Description:
Tiny JavaScript library to report activity of user in the browser
(away, idle, not looking at webpage, in a different tab, etc). that is independent of any
other JavaScript libraries such as jQuery.
Visual Studio users can get it from NuGet by:
Install-Package Idle.js

Here is a rough jQuery implementation of tvanfosson's idea:
$(document).ready(function(){
idleTime = 0;
//Increment the idle time counter every second.
var idleInterval = setInterval(timerIncrement, 1000);
function timerIncrement()
{
idleTime++;
if (idleTime > 2)
{
doPreload();
}
}
//Zero the idle timer on mouse movement.
$(this).mousemove(function(e){
idleTime = 0;
});
function doPreload()
{
//Preload images, etc.
}
})

Similar to Peter J's solution (with a jQuery custom event)...
// Use the jquery-idle-detect.js script below
$(window).on('idle:start', function() {
// Start your prefetch, etc. here...
});
$(window).on('idle:stop', function() {
// Stop your prefetch, etc. here...
});
File jquery-idle-detect.js
(function($, $w) {
// Expose configuration option
// Idle is triggered when no events for 2 seconds
$.idleTimeout = 2000;
// Currently in idle state
var idle = false;
// Handle to idle timer for detection
var idleTimer = null;
// Start the idle timer and bind events on load (not DOM-ready)
$w.on('load', function() {
startIdleTimer();
$w.on('focus resize mousemove keyup', startIdleTimer)
.on('blur', idleStart) // Force idle when in a different tab/window
;
]);
function startIdleTimer() {
clearTimeout(idleTimer); // Clear prior timer
if (idle) $w.trigger('idle:stop'); // If idle, send stop event
idle = false; // Not idle
var timeout = ~~$.idleTimeout; // Option to integer
if (timeout <= 100)
timeout = 100; // Minimum 100 ms
if (timeout > 300000)
timeout = 300000; // Maximum 5 minutes
idleTimer = setTimeout(idleStart, timeout); // New timer
}
function idleStart() {
if (!idle)
$w.trigger('idle:start');
idle = true;
}
}(window.jQuery, window.jQuery(window)))

You can do it more elegantly with Underscore.js and jQuery:
$('body').on("click mousemove keyup", _.debounce(function(){
// do preload here
}, 1200000)) // 20 minutes debounce

My answer was inspired by vijay's answer, but is a shorter, more general solution that I thought I'd share for anyone it might help.
(function () {
var minutes = true; // change to false if you'd rather use seconds
var interval = minutes ? 60000 : 1000;
var IDLE_TIMEOUT = 3; // 3 minutes in this example
var idleCounter = 0;
document.onmousemove = document.onkeypress = function () {
idleCounter = 0;
};
window.setInterval(function () {
if (++idleCounter >= IDLE_TIMEOUT) {
window.location.reload(); // or whatever you want to do
}
}, interval);
}());
As it currently stands, this code will execute immediately and reload your current page after 3 minutes of no mouse movement or key presses.
This utilizes plain vanilla JavaScript and an immediately-invoked function expression to handle idle timeouts in a clean and self-contained manner.

All the previous answers have an always-active mousemove handler. If the handler is jQuery, the additional processing jQuery performs can add up. Especially if the user is using a gaming mouse, as many as 500 events per second can occur.
This solution avoids handling every mousemove event. This result in a small timing error, but which you can adjust to your need.
function setIdleTimeout(millis, onIdle, onUnidle) {
var timeout = 0;
startTimer();
function startTimer() {
timeout = setTimeout(onExpires, millis);
document.addEventListener("mousemove", onActivity);
document.addEventListener("keydown", onActivity);
document.addEventListener("touchstart", onActivity);
}
function onExpires() {
timeout = 0;
onIdle();
}
function onActivity() {
if (timeout) clearTimeout(timeout);
else onUnidle();
//since the mouse is moving, we turn off our event hooks for 1 second
document.removeEventListener("mousemove", onActivity);
document.removeEventListener("keydown", onActivity);
document.removeEventListener("touchstart", onActivity);
setTimeout(startTimer, 1000);
}
}
http://jsfiddle.net/9exz43v2/

I had the same issue and I found a quite good solution.
I used jquery.idle and I only needed to do:
$(document).idle({
onIdle: function(){
alert('You did nothing for 5 seconds');
},
idle: 5000
})
See JsFiddle demo.
(Just for information: see this for back-end event tracking Leads browserload)

If you are targeting a supported browser (Chrome or Firefox as of December 2018) you can experiment with the requestIdleCallback and include the requestIdleCallback shim for unsupported browsers.

You could probably hack something together by detecting mouse movement on the body of the form and updating a global variable with the last movement time. You'd then need to have an interval timer running that periodically checks the last movement time and does something if it has been sufficiently long since the last mouse movement was detected.

I wrote a small ES6 class to detect activity and otherwise fire events on idle timeout. It covers keyboard, mouse and touch, can be activated and deactivated and has a very lean API:
const timer = new IdleTimer(() => alert('idle for 1 minute'), 1000 * 60 * 1);
timer.activate();
It does not depend on jQuery, though you might need to run it through Babel to support older browsers.
https://gist.github.com/4547ef5718fd2d31e5cdcafef0208096

(Partially inspired by the good core logic of Equiman's answer.)
sessionExpiration.js
sessionExpiration.js is lightweight yet effective and customizable. Once implemented, use in just one row:
sessionExpiration(idleMinutes, warningMinutes, logoutUrl);
Affects all tabs of the browser, not just one.
Written in pure JavaScript, with no dependencies. Fully client side.
(If so wanted.) Has warning banner and countdown clock, that is cancelled by user interaction.
Simply include the sessionExpiration.js, and call the function, with arguments [1] number of idle minutes (across all tabs) until user is logged out, [2] number of idle minutes until warning and countdown is displayed, and [3] logout url.
Put the CSS in your stylesheet. Customize it if you like. (Or skip and delete banner if you don't want it.)
If you do want the warning banner however, then you must put an empty div with ID sessExpirDiv on your page (a suggestion is putting it in the footer).
Now the user will be logged out automatically if all tabs have been inactive for the given duration.
Optional: You may provide a fourth argument (URL serverRefresh) to the function, so that a server side session timer is also refreshed when you interact with the page.
This is an example of what it looks like in action, if you don't change the CSS.

Try this code. It works perfectly.
var IDLE_TIMEOUT = 10; //seconds
var _idleSecondsCounter = 0;
document.onclick = function () {
_idleSecondsCounter = 0;
};
document.onmousemove = function () {
_idleSecondsCounter = 0;
};
document.onkeypress = function () {
_idleSecondsCounter = 0;
};
window.setInterval(CheckIdleTime, 1000);
function CheckIdleTime() {
_idleSecondsCounter++;
var oPanel = document.getElementById("SecondsUntilExpire");
if (oPanel)
oPanel.innerHTML = (IDLE_TIMEOUT - _idleSecondsCounter) + "";
if (_idleSecondsCounter >= IDLE_TIMEOUT) {
alert("Time expired!");
document.location.href = "SessionExpired.aspx";
}
}

<script type="text/javascript">
var idleTime = 0;
$(document).ready(function () {
//Increment the idle time counter every minute.
idleInterval = setInterval(timerIncrement, 60000); // 1 minute
//Zero the idle timer on mouse movement.
$('body').mousemove(function (e) {
//alert("mouse moved" + idleTime);
idleTime = 0;
});
$('body').keypress(function (e) {
//alert("keypressed" + idleTime);
idleTime = 0;
});
$('body').click(function() {
//alert("mouse moved" + idleTime);
idleTime = 0;
});
});
function timerIncrement() {
idleTime = idleTime + 1;
if (idleTime > 10) { // 10 minutes
window.location.assign("http://www.google.com");
}
}
</script>
I think this jQuery code is perfect one, though copied and modified from above answers!!
Do not forgot to include the jQuery library in your file!

Pure JavaScript with a properly set reset time and bindings via addEventListener:
(function() {
var t,
timeout = 5000;
function resetTimer() {
console.log("reset: " + new Date().toLocaleString());
if (t) {
window.clearTimeout(t);
}
t = window.setTimeout(logout, timeout);
}
function logout() {
console.log("done: " + new Date().toLocaleString());
}
resetTimer();
//And bind the events to call `resetTimer()`
["click", "mousemove", "keypress"].forEach(function(name) {
console.log(name);
document.addEventListener(name, resetTimer);
});
}());

The problem with all these solutions, although correct, is they are impractical, when taking into account the session timeout valuable set, using PHP, .NET or in the Application.cfc file for ColdFusion developers.
The time set by the above solution needs to sync with the server-side session timeout. If the two do not sync, you can run into problems that will just frustrate and confuse your users.
For example, the server side session timeout might be set to 60 minutes, but the user may believe that he/she is safe, because the JavaScript idle time capture has increased the total amount of time a user can spend on a single page. The user may have spent time filling in a long form, and then goes to submit it. The session timeout might kick in before the form submission is processed.
I tend to just give my users 180 minutes, and then use JavaScript to automatically log the user out. Essentially, using some of the code above, to create a simple timer, but without the capturing mouse event part.
In this way my client side and server-side time syncs perfectly. There is no confusion, if you show the time to the user in your UI, as it reduces. Each time a new page is accessed in the CMS, the server side session and JavaScript timer are reset. Simple and elegant. If a user stays on a single page for more than 180 minutes, I figure there is something wrong with the page, in the first place.

You can use the below mentioned solution
var idleTime;
$(document).ready(function () {
reloadPage();
$('html').bind('mousemove click mouseup mousedown keydown keypress keyup submit change mouseenter scroll resize dblclick', function () {
clearTimeout(idleTime);
reloadPage();
});
});
function reloadPage() {
clearTimeout(idleTime);
idleTime = setTimeout(function () {
location.reload();
}, 3000);
}

I wrote a simple jQuery plugin that will do what you are looking for.
https://github.com/afklondon/jquery.inactivity
$(document).inactivity( {
interval: 1000, // the timeout until the inactivity event fire [default: 3000]
mouse: true, // listen for mouse inactivity [default: true]
keyboard: false, // listen for keyboard inactivity [default: true]
touch: false, // listen for touch inactivity [default: true]
customEvents: "customEventName", // listen for custom events [default: ""]
triggerAll: true, // if set to false only the first "activity" event will be fired [default: false]
});
The script will listen for mouse, keyboard, touch and other custom events inactivity (idle) and fire global "activity" and "inactivity" events.

I have tested this code working file:
var timeout = null;
var timee = '4000'; // default time for session time out.
$(document).bind('click keyup mousemove', function(event) {
if (timeout !== null) {
clearTimeout(timeout);
}
timeout = setTimeout(function() {
timeout = null;
console.log('Document Idle since '+timee+' ms');
alert("idle window");
}, timee);
});

Is it possible to have a function run every 10 seconds, and have that check a "counter" variable? If that's possible, you can have an on mouseover for the page, can you not?
If so, use the mouseover event to reset the "counter" variable. If your function is called, and the counter is above the range that you pre-determine, then do your action.

Here is the best solution I have found:
Fire Event When User is Idle
Here is the JavaScript:
idleTimer = null;
idleState = false;
idleWait = 2000;
(function ($) {
$(document).ready(function () {
$('*').bind('mousemove keydown scroll', function () {
clearTimeout(idleTimer);
if (idleState == true) {
// Reactivated event
$("body").append("<p>Welcome Back.</p>");
}
idleState = false;
idleTimer = setTimeout(function () {
// Idle Event
$("body").append("<p>You've been idle for " + idleWait/1000 + " seconds.</p>");
idleState = true; }, idleWait);
});
$("body").trigger("mousemove");
});
}) (jQuery)

I use this approach, since you don't need to constantly reset the time when an event fires. Instead, we just record the time, and this generates the idle start point.
function idle(WAIT_FOR_MINS, cb_isIdle) {
var self = this,
idle,
ms = (WAIT_FOR_MINS || 1) * 60000,
lastDigest = new Date(),
watch;
//document.onmousemove = digest;
document.onkeypress = digest;
document.onclick = digest;
function digest() {
lastDigest = new Date();
}
// 1000 milisec = 1 sec
watch = setInterval(function() {
if (new Date() - lastDigest > ms && cb_isIdel) {
clearInterval(watch);
cb_isIdle();
}
}, 1000*60);
},

Based on the inputs provided by equiman:
class _Scheduler {
timeoutIDs;
constructor() {
this.timeoutIDs = new Map();
}
addCallback = (callback, timeLapseMS, autoRemove) => {
if (!this.timeoutIDs.has(timeLapseMS + callback)) {
let timeoutID = setTimeout(callback, timeLapseMS);
this.timeoutIDs.set(timeLapseMS + callback, timeoutID);
}
if (autoRemove !== false) {
setTimeout(
this.removeIdleTimeCallback, // Remove
10000 + timeLapseMS, // 10 secs after
callback, // the callback
timeLapseMS, // is invoked.
);
}
};
removeCallback = (callback, timeLapseMS) => {
let timeoutID = this.timeoutIDs.get(timeLapseMS + callback);
if (timeoutID) {
clearTimeout(timeoutID);
this.timeoutIDs.delete(timeLapseMS + callback);
}
};
}
class _IdleTimeScheduler extends _Scheduler {
events = [
'load',
'mousedown',
'mousemove',
'keydown',
'keyup',
'input',
'scroll',
'touchstart',
'touchend',
'touchcancel',
'touchmove',
];
callbacks;
constructor() {
super();
this.events.forEach(name => {
document.addEventListener(name, this.resetTimer, true);
});
this.callbacks = new Map();
}
addIdleTimeCallback = (callback, timeLapseMS) => {
this.addCallback(callback, timeLapseMS, false);
let callbacksArr = this.callbacks.get(timeLapseMS);
if (!callbacksArr) {
this.callbacks.set(timeLapseMS, [callback]);
} else {
if (!callbacksArr.includes(callback)) {
callbacksArr.push(callback);
}
}
};
removeIdleTimeCallback = (callback, timeLapseMS) => {
this.removeCallback(callback, timeLapseMS);
let callbacksArr = this.callbacks.get(timeLapseMS);
if (callbacksArr) {
let index = callbacksArr.indexOf(callback);
if (index !== -1) {
callbacksArr.splice(index, 1);
}
}
};
resetTimer = () => {
for (let [timeLapseMS, callbacksArr] of this.callbacks) {
callbacksArr.forEach(callback => {
// Clear the previous IDs
let timeoutID = this.timeoutIDs.get(timeLapseMS + callback);
clearTimeout(timeoutID);
// Create new timeout IDs.
timeoutID = setTimeout(callback, timeLapseMS);
this.timeoutIDs.set(timeLapseMS + callback, timeoutID);
});
}
};
}
export const Scheduler = new _Scheduler();
export const IdleTimeScheduler = new _IdleTimeScheduler();

As simple as it can get, detect when the mouse moves only:
var idle = false;
document.querySelector('body').addEventListener('mousemove', function(e) {
if(idle!=false)
idle = false;
});
var idleI = setInterval(function()
{
if(idle == 'inactive')
{
return;
}
if(idle == true)
{
idleFunction();
idle = 'inactive';
return;
}
idle = true;
}, 30000); // half the expected time. Idle will trigger after 60 s in this case.
function idleFuntion()
{
console.log('user is idle');
}

Here is an AngularJS service for accomplishing in Angular.
/* Tracks now long a user has been idle. secondsIdle can be polled
at any time to know how long user has been idle. */
fuelServices.factory('idleChecker',['$interval', function($interval){
var self = {
secondsIdle: 0,
init: function(){
$(document).mousemove(function (e) {
self.secondsIdle = 0;
});
$(document).keypress(function (e) {
self.secondsIdle = 0;
});
$interval(function(){
self.secondsIdle += 1;
}, 1000)
}
}
return self;
}]);
Keep in mind this idle checker will run for all routes, so it should be initialized in .run() on load of the angular app. Then you can use idleChecker.secondsIdle inside each route.
myApp.run(['idleChecker',function(idleChecker){
idleChecker.init();
}]);

Surely you want to know about window.requestIdleCallback(), which queues a function to be called during a browser's idle periods.
You can see an elegant usage of this API in the Quicklink repo.
const requestIdleCallback = window.requestIdleCallback ||
function (cb) {
const start = Date.now();
return setTimeout(function () {
cb({
didTimeout: false,
timeRemaining: function () {
return Math.max(0, 50 - (Date.now() - start));
},
});
}, 1);
};
The meaning of the code above is: if the browser supports requestIdleCallback (check the compatibility), uses it. If is not supported, uses a setTimeout(()=> {}, 1) as fallback, which should queue the function to be called at the end of the event loop.
Then you can use it like this:
requestIdleCallback(() => {...}, {
timeout: 2000
});
The second parameter is optional, you might want to set a timeout if you want to make sure the function is executed.

You could probably detect inactivity on your web page using the mousemove tricks listed, but that won't tell you that the user isn't on another page in another window or tab, or that the user is in Word or Photoshop, or WoW and just isn't looking at your page at this time.
Generally, I'd just do the prefetch and rely on the client's multi-tasking. If you really need this functionality, you do something with an ActiveX control in Windows, but it's ugly at best.

Debounce is actually a great idea! Here is a version for jQuery-free projects:
const derivedLogout = createDerivedLogout(30);
derivedLogout(); // It could happen that the user is too idle)
window.addEventListener('click', derivedLogout, false);
window.addEventListener('mousemove', derivedLogout, false);
window.addEventListener('keyup', derivedLogout, false);
function createDerivedLogout (sessionTimeoutInMinutes) {
return _.debounce( () => {
window.location = this.logoutUrl;
}, sessionTimeoutInMinutes * 60 * 1000 )
}

How to pause and resume jquery interval

I have made a custom slider with jQuery. For this I have used setInterval function:
timer = setInterval(function() {}, 8000);
But I cannot pause and resume the interval. I have 2 buttons (play, pause) which I want to use for. Lets say I click pause after 3 sec, and then resume it. So it should stay in that slider for 5 more seconds and then go to the next one and continue 8 seconds each. I have seen this kinda slider with mouseover pause, but can't do it by myself. I have tried this:
clearInterval(timer);
But this seems reset the interval, don't pause. Can anyone help :)

I'm not entirely sure that's something native to jQuery, however, you could use a flag to pause it, and check in your setInterval whether to execute.
Edit:
Found something that might be useful to you, the jquery-timer
Alternitively, you can keep track of the id set by setInterval, and clear out out when you'd like to pause. Then you can set it again when you wish to resume:
var id = window.setInterval(<code>); //create
window.clearInterval(id); //pause
id = window.setInterval(<code>); //resume

there are two ways of accomplish this:
Clearing the interval everytime you pause and starting a new interval when you resume it.
Having a flag to tell the function in the interval when it is paused and it should not do anything.
The first solution would work like this:
let intervalId = false;
const intervalLength = 8000; // 8 seconds
function intervalFunction () {
// do stuff.
}
startButton.onclick = function () {
if (intervalId === false) {
intervalId = setInterval(intervalFunction, intervalLength);
}
}
pauseButton.onclick = function () {
if (intervalId !== false) {
clearInterval(intervalId);
intervalId = false;
}
}
// auto start it:
intervalId = setInterval(intervalFunction, intervalLength);
The second solution would work like this:
var isRunning = true;
var interval = setInterval(function() {
if (!isRunning) {
// not running, do nothing
} else {
// it is running, do stuff.
}
}, 8000);
pauseButton.onclick = function () {
isRunning = false;
};
startButton.onclick = function () {
isRunning = true;
};

I am not complete sure, that what you are asking for, is the right thing you are showing us... setInterval basically is pure native javascript and in my opinion not worth using! If you wan't to set your timeouts via jquery try this link: http://jchavannes.com/jquery-timer. You can find usages there...
Now on to your problem... you need a state to check wether the slider has to slide or not... simply set a bool like this...
var timer;
var doSlide = false;
var i = 0;
function Slide(){
timer = setTimeout(function(){
if(doSlide == true){
Slide();
i++; // Same as i = i + 1
console.log('Sliding');
if(i == 3) AbortSlide(); /* Abort on third slide! Dont use this in your logic!*/
} else if(doSlide == false){
console.log('Sliding aborted untill next RunSlide() call!')
clearTimeout(timer);
}
},1000);
}
function AbortSlide(){
doSlide = false;
i = 0; // Resetting the count! Dont use this in your logic!
}
function RunSlide(){
doSlide = true;
Slide();
}
RunSlide();
You could also empty the interval in the abort method:
function AbortSlide(){
doSlide = false;
clearTimeout(timer);
i = 0; // Resetting the count! Dont use this in your logic!
}
Here is a working fiddle i made for you to understand what timers and intervals are for: https://jsfiddle.net/q5qzmv68/7/
Hope this helps! Cheers!

Duplicated countdown timer after click event

I have this function:
var secondsRemaining = 45;
function countdown(secondsRemaining) {
var seconds = secondsRemaining;
if (secondsRemaining > 0) {
$('.timer > div').html(seconds);
secondsRemaining--;
} else {
if (secondsRemaining == 0) {
// Times up ....
}
}
setInterval(function() {
countdown(secondsRemaining);
}, 1000);
}
I am running the function in the Document ready function with:
countdown(secondsRemaining);
and also I run it again after I clicked for answer.
the problem is that I have 2 countdown timer now running simultaneously, new one that start from 45 seconds and the old one that continue from where it was.

Use clearInterval()
First, store the interval id of the first setInterval():
var secondsRemaining = 45;
function countdown(secondsRemaining) {
var seconds = secondsRemaining;
if (secondsRemaining > 0) {
$('.timer > div').html(seconds);
secondsRemaining--;
} else {
if (secondsRemaining == 0) {
// Times up ....
}
}
myinterval=setInterval(function() { //myint now contains the interval id
countdown(secondsRemaining);
}, 1000);
}
Now, when the user clicks, before setting up a new interval, cancel the first one with clearInterval():
button.onclick=function(){
//do stuff
clearInterval(myinterval)
setInterval(function() {
countdown(secondsRemaining);
}, 1000);
// do stuff
}

Sorry I don't really understand the way you have phrased the question seems to say that you intentionally want to start two time events, one when the document has loaded and the other when you click answer which are both outputting to the same element.
If the problem is you want it to have the output in two different elements then you could pass an argument of the element you could use:
countdown($('.pick-me'), secondsRemaining);
If you want to use the same element, then you could always clear the interval on each click and then set the interval for the new event, just got the update and seen Manishearths response so wont go into any more detail about it as that's probably the answer you are looking for.