Javascript: Call a function after specific time period

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)

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

Execute function FetchData() once after 1000 milliseconds:

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

Execute function FetchData() repeatedly every 1000 milliseconds:

setInterval( FetchData, 1000);