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setTimeout, setInterval

  1. setTimeout :

Think of setTimeout as a way to tell your computer to do something (like saying "Hello") after waiting for a certain amount of time (let's say 5 seconds). It's like setting an alarm clock for your computer code.

Syntax :

setTimeout(callbackfunction, time);

Example :

<!DOCTYPE html>
<html>
<head>
    <title>setTimeout</title>
</head>
<body>
    <script>
       function sayHello(){
        console.log("Hello");
       }

       console.log('A');
       setTimeout(sayHello, 5000);
       console.log('B')
    </script>
</body>
</html>

Output :

A
B
Hello

Line no 8, The code starts running, and A is printed to the console.

Then, it encounters setTimeout, which tells it to wait for 5 seconds before running the sayHello function.

While waiting for those 5 seconds, the code continues to execute, so B is printed immediately after A.

After the 5-second delay expires, the sayHello function is executed, printing Hello to the console.

Example :

<!DOCTYPE html>
<html>
<head>
    <title>setTimeout</title>
</head>
<body>
    <script>
       function sayHello(){
        console.log("Hello");
       }
       setTimeout(sayHello, 5000);
    </script>
</body>
</html>

Output :

Hello

This code defines a function sayHello that says Hello when called. Then, it uses setTimeout to wait for 5 seconds and then calls sayHello, resulting in Hello being printed to the console after the delay.

  1. setInterval :

setInterval is like a repeating alarm. You tell your computer to do something (say "Hello") every few seconds (let's say every 5 seconds). It keeps doing it over and over, like a timer that beeps regularly.

setInterval(callbackfunction, time);

Example :

<!DOCTYPE html>
<html>
<head>
    <title>setInterval</title>
</head>
<body>
    <script>
       function sayHello(){
        console.log("Hello");
       }
       setInterval(sayHello, 5000);
    </script>
</body>
</html>

Output :

Hello
Hello
Hello
Hello
Hello
Hello
...

In the abouve example, The setInterval function to repeatedly execute the sayHello function at a regular interval of 5 seconds (5000 milliseconds).You define a function called sayHello, which print "Hello" to the console when executed. setInterval(sayHello, 5000) is used to set up an interval. It instructs the JavaScript engine to execute the sayHello function every 5000 milliseconds (5 seconds).