Schedule task with setTimeout and setInterval using javascript

profileTaimoor Sattar

The setTimeout and setInterval functions in JavaScript can schedule the task. We main difference between setTimeout and setInterval functions is as below:

  • setTimeout: execute the function after waiting for a certain amount of time. It will execute the function once.
  • setInterval: It executes the function repeatedly after waiting for a certain amount of time.

lets we have a function that alerts message on the browser and can be defined in javascript as below:

function alertMsg(){
  alert("I am an alert box!!");
}

We can execute the alert() function using SetTimeout and setInterval after waiting for some time.

setTimeout

In Javascript, we can write the setTimeout function as below

setTimeout(alertMsg, 1000); // Will alert once, after a second.

We don't need to clear setTimeout as it only executes the function once.

setInterval

In JavaScript, we can write the setInterval function as below:

var intervalID = setInterval(alertMsg, 1000); // Will alert every second.

If we want to clear the setInterval to execute the function repeatedly, we can write the below command in javascript:

clearInterval(intervalID); // Will clear the timer.

If we want to execute the function once using setInterval() function, we can rewrite our function as below:

function alertMsg(){
  alert("I am an alert box!!");
  clearInterval(intervalID);
}