JavaScript setInterval method with some example

1 minute read


JavaScript provides a built-in method called setInterval that allows you to execute a function or a piece of code repeatedly at a specified time interval. This can be useful for a variety of tasks, such as updating the content of a webpage, polling a server for new data, or animating an element on the page.


To use setInterval, you simply need to pass a function or a code block as the first argument, and the time interval (in milliseconds) as the second argument. Here’s a simple example:

setInterval(() => {
  console.log("Hello, world!");
}, 1000);

In this example, the setInterval method will execute the arrow function every 1000 milliseconds (or 1 second), logging the message “Hello, world!” to the console.

You can also pass a regular function as the first argument to setInterval, like this:

function sayHello() {
  console.log("Hello, world!");
setInterval(sayHello, 1000);

This code will have the same effect as the previous example, but using a named function instead of an arrow function.

Another useful feature of setInterval is that it returns a unique ID that you can use to stop the interval using the clearInterval method. Here’s an example:

const intervalID = setInterval(() => {
  console.log("Hello, world!");
}, 1000);

setTimeout(() => {
}, 5000);

In this code, we store the interval ID returned by setInterval in a variable called intervalID. Then, after 5 seconds (5000 milliseconds) have elapsed, we use the clearInterval method to stop the interval by passing the intervalID variable as an argument.

Finally, you can also pass arguments to the function being executed by setInterval. Here’s an example:

let count = 0;
function incrementCount(step) {
  count += step;
  console.log(`Count is now ${count}`);

setInterval(incrementCount, 1000, 2);

In this example, we’re using the incrementCount function to increment a count variable by a specified step. We pass the value 2 as the third argument to setInterval, which is then passed as the step argument to incrementCount.

These are just a few examples of how you can use the setInterval method in JavaScript to execute code at a specified time interval. Whether you’re updating the content of a webpage or animating an element, setInterval is a powerful tool that can help you achieve your goals.