Javascript: Call a function after specific time period

Question

In JavaScript, How can I call a function after a specific time interval?

Here is my function I want to run:

function FetchData() {
}

Answer 1

You can use JavaScript Timing Events to call function after certain interval of time:

This shows the alert box every 3 seconds:

setInterval(function(){alert("Hello")},3000); 

You can use two method of time event in javascript.i.e.

1. setInterval(): executes a function, over and over again, at specified time intervals
2. setTimeout() : executes a function, once, after waiting a specified number of milliseconds

Answer 2

Execute function FetchData() once after 1000 milliseconds:

setTimeout( function() { FetchData(); }, 1000);

Execute function FetchData() repeatedly every 1000 milliseconds:

setInterval( FetchData, 1000);

Answer 3

ECMAScript 6 introduced arrow functions so now the setTimeout() or setInterval() don't have to look like this:

setTimeout(function() { FetchData(); }, 1000)

Instead, you can use annonymous arrow function which looks cleaner, and less confusing:

setTimeout(() => {FetchData();}, 1000)

Answer 4

sounds like you're looking for setInterval. It's as easy as this:

function FetchData() {
  // do something
}
setInterval(FetchData, 60000);

if you only want to call something once, theres setTimeout.

Answer 5

Timeout:

setTimeout(() => {
   console.log('Hello Timeout!')
}, 3000);

Interval:

setInterval(() => {
   console.log('Hello Interval!')
}, 2000);