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Introduction
In JavaScript, the setInterval() function is a built-in method used to repeatedly execute a specified function or code block at fixed time intervals. It continues to run until explicitly stopped using clearInterval(). This feature is useful for creating timers, animations, and periodic tasks in web applications, making it essential for dynamic behavior on web pages.
Running a program later or periodically is possible using JS. This is called "scheduling a call" or "scheduling a function call". This article will cover the Javascriptsetintervel() method for scheduling a call. Before moving on to the method, let’s briefly discuss scheduling a call.
What is Scheduling a Call in Javascript?
There are several cases in which a coder might choose to delay the execution of a function rather than call it immediately. This type of action is referred to as scheduling a call in JS.
JS framework provides two ways to schedule a call.
Using the javascript setTimeout() method enables us to execute a method once after the interval.
Using the javascript setInterval() method, With the help of setInterval, we can run a function repeatedly, beginning after the interval and repeating continuously at the given time.
Here we will only discuss the javascript setIntervel() method. To learn more, you can visit our article on Scheduling.
What is Javascript SetInterval()?
One can periodically execute a function using the javascript setInterval() method. After a fixed interval of time, the function begins to execute, and at that point, it repeats the function call continuously.
Syntax of SetInterval() in Javascript
The syntax of the javascript setInterval() method is as follows:
Here is the code to display a dialogue box every four seconds.
<!DOCTYPE html>
<html>
<head>
<title> setInterval() method </title>
</head>
<body>
<h1> Code Studio</h1>
<h3> The setInterval() method </h3>
<p> The time interval for the dialogue box is four seconds. </p>
<script>
let msg = setInterval(CodingNinjas, 4000);
function CodingNinjas() {
alert(" Welcome to the Coding Ninjas Studio Library. ");
}
</script>
</body>
</html>
You can also try this code with Online Javascript Compiler
The nested setTimeout() method in JS can be used as the alternative to javascript SetInterval() method.
One can use the following format to use the nested setTimeout() method.
let interval = 1000; //first time
let function = setTimeout(function request() {
if (request failed) {
interval += 1000; //second request
}
function = setTimeout(request, interval);
}, interval);
You can also try this code with Online Javascript Compiler
Request failed. Retrying in 2 seconds.
Request failed. Retrying in 3 seconds.
Request failed. Retrying in 4 seconds.
...
The nested setTimeout() method is more flexible than the javascript setInterval() method. As you can see, in the second request, the delay depends on the response to the first request.
What is Garbage Collection?
When you pass a function to the javascript setInterval() function, an internal reference is created. The scheduler of the system stores this generated reference.
Despite the fact that there are no other references to the function, it stops it from being garbage collected.
Until the javascript clearInterval() method is invoked, the setInterval() function remains in memory.
// until the scheduler executes the function, it remains in the memory.
setTimeout(function()/code {arguments}, 100);
You can also try this code with Online Javascript Compiler
Even if the scheduled task is very small, it is preferable to cancel it when we no more require it. When a function refers to the external function, external variables also exist. They could use a lot more memory than the actual function.
Application of setInterval() in Javascript
There are many applications that make use of JavaScript's setInterval() function, including:
Animations: It can be made by repeatedly changing an element's position, size, or colour on a webpage using the setInterval() function.
Real-time data updates: The setInterval() function can be used to periodically fetch data from a server or API and update the application's user interface (UI) with the new information.
Timer countdowns: setInterval() can be used to decrement a timer countdown that is displayed on a webpage at regular intervals until it reaches zero.
Chat programmes: setInterval() can be used to periodically check for new messages in a chat programme and update the UI with them.
Games: The setInterval() function can be used to move objects, detect collisions, and repeatedly update the game state.
Audio and video players' progress bars can be updated at predetermined intervals by using the setInterval() function.
Automatic slide shows: By repeatedly changing the displayed image after a predetermined interval, setInterval() can be used to create automatic slide shows on a webpage.
When a function is repeated repeatedly, like animations, the setInterval() function is commonly used to set a delay. After a fixed interval of time, the function begins to execute, and at that point, it repeats the function call continuously.
Can we pause setInterval in JavaScript?
No, setInterval cannot be paused directly in JavaScript. However, you can simulate a pause by using clearInterval to stop it temporarily and then restart it using another setInterval when needed.
How do you cancel a setTimeout or setInterval in JavaScript?
To cancel a setTimeout or setInterval, you use the clearTimeout or clearInterval function, respectively, and pass the ID returned when the timer was initially set.
What is setTimeout and setInterval in JavaScript?
setTimeout executes a function after a specified delay, while setInterval repeatedly executes a function at set intervals until explicitly stopped using clearInterval. Both functions are used for timed execution in JavaScript.
Conclusion
In this article, we explored the setInterval() function in JavaScript, understanding its role in executing code at specified intervals. We discussed how it works, its syntax, and practical examples to help implement repeated actions in web applications. Proper use of setInterval() ensures efficient and responsive execution of timed tasks.
In this article, we extensively discussed the javascript setInterval() function.
We hope this blog has helped you with your interview. We recommend you visit our articles on different topics of Javascript, such as
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