JavaScript timer

The JavaScript can use timers to execute code at a specified time interval or after a certain delay. There are two commonly used timer functions: setTimeout() and setInterval().

1. setTimeout():
The setTimeout() function is used to execute a function or evaluate an expression after a specified delay.

Syntax:

setTimeout(function, delay);

Example:

function sayHello() {
  console.log("Hello!");
}

// Execute the sayHello function after a delay of 2000 milliseconds (2 seconds)
setTimeout(sayHello, 2000);

In this example, the sayHello function will be executed after a delay of 2 seconds.

2. setInterval():
The setInterval() function is used to repeatedly execute a function or evaluate an expression at a specified interval.

Syntax:

setInterval(function, interval);

Example:

function sayHello() {
  console.log("Hello!");
}

// Execute the sayHello function every 1000 milliseconds (1 second)
setInterval(sayHello, 1000);

In this example, the sayHello function will be executed every 1 second.

Both setTimeout() and setInterval() return a unique identifier, known as the timer ID. You can use this ID to stop the timer using the clearTimeout() or clearInterval() functions.

Example:

var timerId = setTimeout(function() {
  console.log("Timer finished!");
}, 5000);

// Stop the timer before it completes
clearTimeout(timerId);

In this example, the setTimeout() function returns a timer ID that is stored in the timerId variable. The clearTimeout() function is then called to stop the timer before it completes.

Note: It’s important to clear timers when they are no longer needed to prevent memory leaks and unnecessary execution of code.