The setInterval() method, spread across window and worker interfaces, repeatedly calls a function or executes a code snippet, with a fixed time delay between each call. It returns an interval ID ID, which uniquely identifies the interval, so you can remove it later by calling clearInterval() . This method is defined by the WindowOrWorkerGlobalScope mixin.

Syntax

Parameters

note: Passing additional arguments to setInterval() in the first syntax does not work in Internet Explorer 9 and earlier. If you want to give this functionality to your add-on, you should use the polyfill (see the section).

return value

intervalID is numeric, non-zero value which identifies the timer created by the call to setInterval() ; this value can be passed to cancel the timeout.

We can also change it so that setInterval() and setTimeout() share the sam pool of IDs, and that clearInterval() and clearTimeout() can technically be used interchangeably. For clarity, however, you should try to always match them to avoid confusion when maintaining your code.

note: The delay argument is converted to a signed 32-bit integer The effective term is set to 2147483647 ms, so the insertion is like a member insertion in the IDL.

Examples

Example 1: Basic syntax

Next steps demonstrate setInterval() "s basic syntax.

Var intervalID = window.setInterval(myCallback, 500, "Parameter 1", "Parameter 2"); function myCallback(a, b) ( // Your code here // Parameters are purely optional. console.log(a); console.log(b); )

Example 2: Alternating two colors

The next stop Calls flashtext() function once a second until the Stop button is pressed.

Example 3: Typewriter simulation

The footprints of the typical types of the drukar on the first one are different and the most common types are included in the NodeList, as they represent the sing group of selectors.

CopyLeft 2012 by Mozilla Developer Network

[ play | Pause | Terminate ]

JavaScript Typewriter

callback arguments

Looking ahead, Internet Explorer 9 doesn't even listen for arguments to a callback function in a single setTimeout() or setInterval() . The following IE-specific code demonstrates as a method for overcoming bridging. In order to speed up the proximity to the offensive code to the list.

More opportunities to use anonymous functions to run your callback, but it's a bit more expensive. Example:

Var intervalID = setInterval(function() ( myFunc("one", "two", "three"); ), 1000); var intervalID = setInterval(function(arg1) ().bind(undefined, 10), 1000);

Inactive tabs

Starting in Gecko 5.0 (Firefox 5.0 / Thunderbird 5.0 / SeaMonkey 2.2), the terms are clamped to fire no more often than once per second in inactive tabs.

The "this" problem

If you pass the method before setInterval() or if there is any other function, you will need to introduce what it means. See more details in JavaScript.

Explanation

The code executed by setInterval() runs in a separate execution context than the function from which it was called. As a last resort, the key signal for function names is set to a window (or global) object, it is not the same as this value for the function that called setTimeout . Press on the stepping butt (which is the victorious setTimeout() instead of setInterval() - food, in fact, for quiet, which works):

MyArray = ["zero", "one", "two"]; myArray.myMethod = function (sProperty) ( alert(arguments.length > 0 ? this : this); ); myArray.myMethod(); // Prints "zero,one,two" myArray.myMethod(1); // Prints "one" setTimeout(myArray.myMethod, 1000); // prints "" after 1 second setTimeout(myArray.myMethod, 1500, "1"); // prints "undefined" after 1.5 seconds // passing the "this" object with .call won't work // because this will change the value of this inside setTimeout itself // while we want to change the value of this inside myArray.myMethod // in fact, it will be for error error setTimeout code expects this to be the window object: setTimeout.call(myArray, myArray.myMethod, 2000); // error: "NS_ERROR_XPC_BAD_OP_ON_WNPRO object" setTimeout.call(myArray , myArray.myMethod, 2500, 2); // same error

As you can see, there is no way to get your object to callback functions in a JavaScript alliance.

A possible solution

A possible way to solve the " this " problem is to replace the two native setTimeout() or setInterval() global functions with two non-native ones that enable their invocation via the Function.prototype.call method. The following example shows a possible replacement:

// Allow "target" object to be captured via JavaScript timers var __nativeST__ = window.setTimeout, __nativeSI__ = window.setInterval; window.setTimeout = function (vCallback, nDelay /*, argumentToPass1, argumentToPass2, etc. */) ( var oThis = this, aArgs = Array.prototype.slice.call(arguments, 2); return __nativeST__(vCallback in () ( vCallback.apply(oThis, aArgs); ) : vCallback, nDelay); ); window.setInterval = function (vCallback, nDelay /*, argumentToPass1, argumentToPass2, etc. */) ( var oThis = this, aArgs = Array.prototype.slice.call(arguments, 2); return __nativeSI__(vCallback in () ( vCallback.apply(oThis, aArgs); ) : vCallback, nDelay); );

You can also replace the HTML5 standard transition of arbitrary arguments to the callback function timers in IE. So they can be used as non-standard-compliant polyfills also. See the for a standard-compliant polyfill.

New feature test:

MyArray = ["zero", "one", "two"]; myArray.myMethod = function (sProperty) ( alert(arguments.length > 0 ? this : this); ); setTimeout(alert, 1500, "Hello world!"); // standard use of setTimeout and setInterval is preserved, but... setTimeout.call(myArray, myArray.myMethod, 2000); // Prints "zero,one,two" after 2 seconds setTimeout.call(myArray, myArray.myMethod, 2500, 2); // Prints "two" after 2.5 seconds

For more complex but still modular version of it ( Daemon) see JavaScript Daemons Management . This more complex version is nothing but a big and scalable collection of methods for the Daemon constructor. However, the Daemon constructor itself is nothing but a clone of MiniDaemon with an added support for init and start Functions declared during the instantiation of the daemon . So the MiniDaemon framework remains the recommended way for simple animations, because Daemon without this collection of methods, it is basically a clone of it.

minidaemon.js

MiniDaemon passes arguments to callback function. As you practice with it with browsers, as they naturally do not support this character, use one of the methods that are developed.

Syntax

var myDaemon = New MiniDaemon( thisObject, callback[ , rate [, length]]);

Description

Usage notes

The SetInterval() function is usually hacked to set up for functions, such as running again and again, as well as animations. You can turn on the hour by calling WindowsOrWorkerGlobalScope.clearInterval() .

If you wish to have your function is called once after the specified delay, use .

Delay restrictions

Tse mozhe buti is possible for timchasovyh dzvinkiv; Well, the callback for setInterval() can be set to turn callInterval() to run anytime soon, hit the next time it stops. Duration, once intervals is always five times slower, the browser will automatically set the 4 ms minimum value for an hour.

Browsers can give you more stringent minimum values ​​for the hour under certain circumstances, if you don't want to be guilty. Note also that the actual amount of time that elapses between calls to callback may be longer than the given delay ; Read more Reasons for delays longer than specified in WindowOrWorkerGlobalScope.setTimeout() for examples.

Ensure that execution duration is shorter than interval frequency

If it's possible that your logical one can mean triviality before the end of the day, it will be called, because you're called a function called setTimeout() . For example, as a rule, setInterval() to the tow on the remote server with a stretch of 5 seconds, the term, on the wrong server, and on the other hand, you can request a retry to complete in a new run for the whole hour. So, you can find out about those that you require mutual drinks, which you need to restore in order.

Dzherelo: http://learn.javascript.ru/settimeout-setinterval

May all JavaScript sales have an internal timer-scheduler, which allows you to set a week-click function through a task period of an hour.

Zocrema, the possibility is supported by browsers and Node.JS servers.

setTimeout

Syntax:

Parameters:

• func/code
  • A function or a row of code for a visualization.
  • Row podtremuєtsya for summіnostі, vikoristovuvat її not recommended.
• delay
  • Trim in milliseconds, 1000 milliseconds equals 1 second.
• arg1, arg2…
  • Arguments that need to be passed to the function. Not supported in IE9.
  • The function will expire in an hour, if the delay parameter has an effect.

For example, the next code would be alert("Hello") in one second:

Since the first argument is in a row, the interpreter creates an anonymous function in the third row.

So such a record works like this:

SetTimeout("alert("Hello")", 1000);

Replace them with anonymous functions:

SetTimeout( function()(alert ("Hello")), 1000);

Parameters for the function and context

In all modern browsers, with IE10 enabled, setTimeout allows you to set function parameters.

Butt lower vivede "Hi, I'm Vasya" creased, crim IE9-:

…However, for most of the opinions, we need the support of the old IE, and we do not allow arguments to be shown. Therefore, in order to pass them, wrap the wiki in an anonymous function:

Wikiclick does not pass the this context via setTimeout.

Zokrema, wickklix to the object's method via setTimeout to the global context. It may lead to incorrect results.

For example, we can say user.sayHi() in one second:

The setTimeout keys run the user.sayHi function in the global context, it won't allow access to the object through a chain.

Otherwise, it seems that two setTimeout wikis work the same:

Fortunately, this problem is also easily violated by the creation of intermediate functions:

The wrapping function is used to cross-browser pass the arguments and save the context of the wrapping.

Skasuvannya vikonannya

The setTimeout function rotates the timerId , which can be matched for the match.

Syntax:

ClearTimeout(timerId)

We set a timeout for the offensive butt, and then we see it (changed our minds). As a result, nothing comes up.

setInterval

The setInterval method has a syntax similar to setTimeout.

The sense of argument is the same. Ale, on vіdmіnu setTimeout , vіn run vikonannya funkії not once, but regularly repeat it at intervals of one hour. Zupiniti vikonannya can be clicked:

ClearInterval(timerId)

The stepping butt at startup will display a skin alert for two seconds, do not click on the “Stop” button:

Cherga that overlay of vitklik_v at setInterval

Weekly setInterval (funktion, zatrymka) set the whistleblowing function through the appointment of an hour interval. Ale, there is subtlety here.

Really, the pause between the cycles is less, the interval is lower.

For example, take setInterval(function() ( func(i++) ), 100) . There will be a func skin of 100 ms, so as to increase the value of the lichnik.

A little lower, a red block - the hour of func. Hour between the block - the same hour between the launches of the function, and the smaller one, the jam is installed below!

Therefore, the browser initiates the launch of the function gently in 100ms without adjusting the time of the function itself.

Buvay, vykonannya funktsії occupies more than an hour, nizh zatrimka. For example, the function is foldable, but there is a little stutter. But the function is to avenge the alert/confirm/prompt operators, as if blocking the flow of the alarm. And here tsіkavі rechі begin.

If the launch of the function is not possible, then the browser is busy, it gets in the line and it turns out, just like the browser calls.

The images below are illustrative of those that are required for the function, as long as they are victorious.

Weekly function, setInterval initiation, added in line and negligently, if we can:

Another launch of the function will be performed as soon as the first one is completed:

More than once, do not place a vikonnanny on the line.

If the execution of a function takes more than an hour, the lower the number of planned appointments, then everything costs only once. Also, the “heap” of launches is not seen.

In the image below, setInterval is used to delay the function of 200 ms and set a wake-up call on the line. At 300 ms and 400 ms, the timer is passed again, but nothing else passes.

Weekly setInterval does not guarantee real stutter between vicons.

Buvayut vipadki, if real zatrimka more or less for the task. Vzagali is not a fact that it will be like a zatrimka.

Repeat nesting setTimeout

In vipads, if you need not just a regular repetition, but a catch-up between launches, you will need to re-insert setTimeout with the skin viconan function.

Below is a butt, which looks like an alert with intervals of 2 seconds and between them.

On the hourly line, there will be fixes between launches. Illustration for 100ms trim:

Minimum delay timer

Browser timer may be minimally stuttering. It changes from about zero to 4ms in modern browsers. For older people, you can have more and reach 15ms.

Behind the standard, the minimum stutter is 4ms. So there is no difference between setTimeout(..,1) and setTimeout(..,4) .

The setTimeout and setInterval behaviors have zero-thumb and browser-specific features.

1. Opera, setTimeout(.., 0) are the same as setTimeout(.., 4) . It can be compared below setTimeout(..,2). Tse sooblivist tsgo browser.
2. Internet Explorer's null stutter setInterval(.., 0) does not work. Go for setInterval yourself, then. setTimeout(.., 0) works fine.

Real frequency of spratsovuvannya

Spratsovuvannya can be richer sooner. In a number of fluctuations, the trim can be not 4ms, but 30ms or 1000ms.

Most browsers (desktop ones in Persian) continue to run setTimeout / setInterval when the tab is inactive. If so, a number of them (Chrome, FF, IE10) reduce the minimum timer frequency, up to 1 time per second. To come out, that the “background” depositors have a timer, but rarely.

When using a battery, in a laptop - browsers can also lower the frequency, so that it is easier to disable the code and protect the battery charge. Especially cym vidomy IE. Lowering can be hit for a few times, fallow in the field. When overwhelmed by the JavaScript processor, you may not be able to override the timers. If so, runs of setInterval will be skipped.

Visnovok: at the frequency of 4ms, varto orient, but do not varto open.

Viewing Intervals at the Console

setTimeout(func, 0) trick

This trick is going to go to the annals of JavaScript hacks.

The function is wrapped with setTimeout(func, 0) so that you want to run it after the stream script ends.

On the right is that setTimeout in no way defeats the function in the first place. Vіn less planuє її vikonannya. Ale, the JavaScript interpreter is more likely to override scheduled functions than after overriding a streaming script.

Behind the standard, setTimeout at any time cannot override the function from the timeout to 0. As we said before, the timeout becomes 4ms. Ale smut here the very ones who will ever be vikonnannya at any time will be after the vikonannya of the stream code.

For example:

Together

The setInterval(func, delay) and setTimeout(func, delay) methods allow func to run regularly/once every delay milliseconds.

There are two ways to turn the timer identifier. You can use the quick-click clearInterval/clearTimeout for the zipper.

| | setinterval | setTimeout | || ----------- | ---------- | | Timing | Go weekly strictly behind the timer. As an interpreter of occupations, one week is lost in black. The hour of the end of the function is not guaranteed, that interval after the completion of one start on the cob of another can be changed. | Recursive weekly setTimeout overrides setInterval where a pause is required between cycles. | | Trim Minimum trim: 4ms. | Minimum fade: 4ms. | | Browser specifics IE does not use 0 stutter. Opera has zero stutter equivalent to 4ms, other stutters are processed exactly, including the non-standard 1ms, 2ms and 3ms. |

When programming with scripting language, it is periodically necessary to create a pause - to pause the program for a certain hour, and then continue the robot. For example, VBS and PHP scripts can use the following methods:

VBS: wscript.sleep 1500 (sleep for 1.5 seconds)

PHP: sleep(10); (Zupinka for 10 seconds)

Pіd h podіbnih pauses vykonoyuchu system (PHP or VBS) do nothing. Rozrobnik, having tried it intuitively similar to Javascript, you will be unacceptably chirpy. A typical pardon when trying to pause in Javascript looks like this:

Function badtest() ( for (var i = 1; i< 10; i++) { window.setTimeout("document.getElementById("test1").value += " + i, 900) } }

Do you think that if, during the passage of the cycle of the cherga, you reach the drawing of the cherga number, your setTimeout honestly enter the Javascript robot, check 0.9 sec., add a number to the end of the input field, and then proceed to the robot. But really it's not like that: setIntervalі setTimeout in Javascript, it is necessary to add more than tієї dії (or functions), as indicated by the arms. Our example will look like this:

1. i = 1;
2. add the number "1" to the input field for 0.9 seconds;
3. negaino after the formulation of this task, the cycle went further: i = 2;
4. add the digit "2" to the input field by 0.9 seconds;

negaino means, for example, 1 ms (which is incomprehensibly small, equal to 900 ms): the cycle will carry out your work in a practical way, having created a lot of tasks in the same time. Tse means that all the entries for the "painting" will be completed practically at the same hour, without pauses between adding new numbers. The cycle starts; all fade to 0.9; and shirr - all numbers are arranged in a row one by one.

And how do you properly zasosuvat this time setTimeout? It's complicated. Come call the function recursively(in the middle of the function, the very function), and so that the process is not limited, set the mind teeth (for example, the value of the other number):

Function welltest() ( if (i< 9) { document.getElementById("test2").value += ++i window.setTimeout("welltest()", 400) } }

I change again i to happen to initiate posture function - for example, like this:

The axis is now working as it should (we changed the hour of the trim from 0.9 to 0.4 s). But for similar tasks, it’s more logical to still not stop setTimeout a setInterval(if you want to need two functions):

Function besttest() ( window.i = 0 window.timer1 = window.setInterval("draw()", 400) ) function draw() ( document.getElementById("test3").value += ++i if (i >= 9) clearInterval(window.timer1) )

Features of the Javascirpt Method setInterval for those who do not pass wine “by themselves”, yoga is required to be done by a special method clearInterval. And so it was realized that the very same, the zavdannya vіdkladenoї dії is assigned a special identifier - a timer: window.timer1 = window.setInterval(...) .

Identifiers can be entered in this way by default, using the method setTimeout. All timer identifiers must be recognized one after the other (they must be unique within the browser's streaming window). The same can be done at the end of the day, when the victorious appointments are made, and the appointments can be made in parallel (once at the same time, as the computer has a lot of resources), which in principle is impossible in PHP or VBS.

Axis butt side with a lot of Javascript timers, which can be run one hour: setinterval.htm (Javascript functions in the setinterval.js file). You can start the robot of all timers on the side (menu menu) with the Esc key. All timers of applications are based on “natural” (and not abstract) i++) vіdlіk - hour or vіdstanі. All “anniversaries” are specially synchronized (for accuracy). Timers, which lie in the countryside, wink in the “indicators” and in the menu, which you can see (“vyzhdzhaє”).

VIP menu

Our menu, scho vyzhdzhaє - really vyzhdzhaє (z-pіd "caps"): gaps between the elements are specially filled, schob bachiti, like out of vіїzhdzhaє. Unexpectedly, it turned out that we could not create a smooth transition for the lists of different days - probably due to the low productivity of the computer (AMD Athlon 999 MHz).

It is obvious that it is necessary to finish the beauty of that harmony, so that the lists of different menu items fell out in that very hour. Tobto dowshi lists of guilt vipadati with greater swedishness, short - with less swedishness. It would be possible to implement it like this:

1. We install the last hour of "vision", for example, 200 ms.
2. Even though a list that falls down can have a height of 20 px, obviously, we can drop it down one pixel per 10 ms interval - and even in 200 ms, the entire list will fit.
3. For example, the list that falls, may height 40 px, to be included in the same hour, we are guilty of dropping it down one pixel per 5 ms.

For this logic, like a list that falls, may height 200 px, we are guilty of dropping yoga down one pixel per 1 ms. But such a speed on our computer does not work - the browser simply does not get the new position of the list in a millisecond. So. Javascript is good (what is there to be good?), but the browser (Firefox) is not. Typical situation for the Internet.

Therefore, it’s more or less to take the time to look at the menu, you can only get help, and it’s still unclear how much more swedish computer. But are we to blame for the most expensive? The algorithm (without upgrading the computer's firmware code) goes something like this:

1. Set the top hour to the list view: time = 224 (ms).
2. Set the minimum hour of one interval in the cycle: delay = 3 (ms).
3. Set the minimum margin for the list: offset = 1 (px).
4. We change everything in the fallow time according to the height of the list: 1) increase the hour of the trim (interval) back in proportion to the height and directly in proportion to the high hour time (at a height of 224, the coefficient of advance is 1); 2) even though the height is larger for 40 px, the minimum size is larger in proportion to the height. The constant "40" has been removed by the official way for the most popular computer. Tests on a Pentium 4 CPU 2.53GHz computer showed the same number - 40. Otherwise, the timers go apart, the lists are out of step.

Axis now lists more-mensh viїzhdzhayut. For more or less a similar hour. On the side setinterval.htm.

A axis i Bruce:

Function slide_do(obj, maxtop, offset) ( if (getTopLeft(obj).top< maxtop) { obj.style.top = getTopLeft(obj).top + offset } else { if (obj && obj.timer1) { clearInterval(obj.timer1) obj.timer1 = null } } }

The function itself, which displays tabs in menu lists, is pretty simple. It was only left to launch її approximately in such a row:

ts.timer1 = setInterval(function()(slide_do(ts, maxtop, offset)), delay)

Well, before starting, just calculate all values ​​of maxtop and offset, and also place the list at the mintop position. What does the “front” function do slide() rozmirom 40 rows. And all at once - in the setinterval.js file. So, this crap never works without an attached style file

It's important to understand how to use JavaScript timers. Most of the time, our behavior does not break with our intuitive perceptions of rich flow, and it is connected with it, that the stench is really wound up in the same sweat. Let's take a look at some of the functions, for the help of which we can use timers:

• var id = setTimeout(fn, delay); - Create a simple timer that activates the function after a given stutter. The function rotates a unique ID, for the help of which the timer can be assigned.
• var id = setInterval(fn, delay); - Similar to setTimeout, but continuously calls the function at a given interval (until it is called).
• clearInterval(id); clearTimeout(id); - Accepts the ID timer (turns one of the functions described above) and calls the callback "a.

To give a lot of information to every little one, how to get it, and also to give you a better understanding of the mechanism of robotic asynchrony and JavaScript. on this diagram, vertical representations of hours and milliseconds, blue blocks show blocks of JavaScript code, which is a kind of typing. For example, the first block is ticked in the middle for 18ms, a click on the mouse blocks the ticking for about 11ms and so on.

JavaScript can only override one chunk of code (through the single-threaded nature of the override), while blocking any other asynchronous subroutines. This means that when the asynchronous pod is wrong (such as a click on the mouse, a timer wick or the XMLHttp request is completed), the win is added to the line and later (implementation, of course, varies in the browser's staleness, but let's be clear).

First of all, it is clear that two timers start in the middle of the JavaScript block: setTimeout with a 10ms delay and setInterval with the same delay. It is necessary if the timer starts, it will start at the moment, if the first block of the code has not been completed yet. Be aware, however, that VIN cannot be used directly (it is not possible through single-threading). Natom_st was added, the function was consumed at the black and vykonuetsya at the next available moment.

Also, when the first JavaScript block is over, the block is called a mouse click. Obrobnik tsієї asynchronous podії (but it's asynchronous, to that we can't pass it on) can't be beaten without intermission at the moment, that vin is also spent in the line, like a timer.

After the first block of JavaScript code has been hijacked, the browser asks the “Who is checking for hijacking?” food. At the same time, the collector clicks on the mouse and the timer is rebuked at the station. Browser selects one of them (the clicker) and wins. The timer checks the available portion of the hour at the next hour.

Respect that while the mouse's click capture is still running, use the first interval-callback. So it’s just like a timer-callback, there will be orders from the black. Prote, check that if I spratsyuє interval again (until the timer-callback is available), the win will be deleted from the charts. Yakby all interval-callback" and squandered in the queue while the great piece of code is being checked, it would have led to the fact that a bunch of functions have been established, to check the call without periods of delays between the end of their calls. add one more to the drawing.

In this way, we can watch out for failures if the third time an interval-callback is triggered after this moment, if it fails. This is an important feature to illustrate: the intervals do not count for those who are victorious at once, they will be added to the line without balancing the period of obstruction between the victors.

Nareshti, after another interval-callback is completed, we hope that nothing is left out, that the JavaScript engine is to blame. This means that the browser will check again for new asynchronous subs. Do not traverse for 50ms, de interval-callback will start again. At this moment, there’s nothing to be cleared up, which would block yoga, it won’t work for that.

Let's take a look at an example that illustrates the difference between setTimeout and setInterval.
setTimeout(function()( /* Some long block of code... */ setTimeout(arguments.callee, 10); ), 10); setInterval(function()( /* Some long block of code... */ ), 10);
These two options are equivalent at first glance, but in reality they are not. The code that would setTimeout to set the timeout would be 10ms after the forward loop (it could be larger, but it could not be smaller), just like the code that would setInterval to setInterval to call the skin 10ms ahead of the right, depending on the number of times

Let's recap everything that has been said:
- JavaScript engines are a single-threaded middleware, converting asynchronous inputs into a line, which is cleared up,
- The setTimeout and setInterval functions are fundamentally different in asynchronous code,
- If the timer cannot be beaten at the given moment, it will be laid before the starting point of the break (as it will be done for the bagan zatrimka),
- Intervals (setInterval) can be cycled one by one without a stutter, as it takes more than an hour, a stutter is assigned below.

Everything is extremely important information for distribution. Knowing how the JavaScript engine works, especially the large number of asynchronous sub-pods (which are often used), lays the foundation for encouraging new additions.