JavaScript setTimeout() Method

Last Updated : 22 Jan, 2024

JavaScript setTimeout() method allows you to schedule the execution of a function or the evaluation of a code after a specified delay.

The setTimeout() method calls a function after several milliseconds. setTimeout() is for executing a function once after a specified delay.

Syntax:

setTimeout(function, delay);

Parameters:

function: The function or code snippet to be executed after the specified delay.
delay: The time, in milliseconds, to wait before executing the function.

Return Value:

Returns a Number which is the id of the timer. Use this id with clearTimeout(id) to cancel the timer.

Example 1: Here, the greet function will be executed after a delay of 2000 milliseconds (2 seconds).

Javascript

function greet() {
  console.log("Hello, world!");
}
 
// Call the greet function after 
// 2000 milliseconds (2 seconds)
setTimeout(greet, 2000);

Output: (Will be printed after 2 sec or 2000ms)

Hello, world!

Example 2: Below is the example of popping an up alert, 2 seconds(2000ms) after the user presses the click me button.

HTML

<!DOCTYPE html>
<html lang="en">
 
<head>
    <meta charset="UTF-8">
    <meta name="viewport">
    <title>Document</title>
</head>
 
<body>
    <button onclick="setTimeout(gfg, 2000);">
        Press me
    </button>
    <script>
        function gfg() {
            alert('Welcome to GeeksforGeeks');
        }
    </script>
</body>
 
</html>

Output:

Note: We can stop the execution of the setTimeout() function by using a method called as clearTimeout() or by closing the window.

Example 3: Here, we are using a setTimeout() function and stop its execution using the clearTimeout() function before the execution of the setTimeout().

HTML

<!DOCTYPE html>
<html lang="en">
 
<head>
    <meta charset="UTF-8">
    <meta name="viewport">
    <title>Document</title>
</head>
 
<body>
    <p>Press the stop button 
        before the alert is shown</p>
    <button onclick="val = setTimeout(gfg, 2000);">
        Press me
    </button>
    <button onclick="clearTimeout(val);">
        Stop Execution</button>
    <script>
        function gfg() {
            alert('Welcome to GeeksforGeeks');
        }
    </script>
</body>
 
</html>