Timer in JavaScript

1. Create a Timer With setTimeout() in JavaScript
2. Create a Timer With setInterval() in JavaScript

JavaScript provides two timer functions for executing non-blocking code. JavaScript provides the functions setTimeout() and setInterval(), which execute the specified expression or function after a certain time interval.

In today’s post, we are going to learn more about the JavaScript timer.

Create a Timer With setTimeout() in JavaScript

This is an asynchronous function provided by JavaScript that executes a specific function or section of code after the timer expires. Various reasons cause timeouts to be delayed, like nested timeouts, timeouts in inactive tabs, throttling of tracking scripts, and deferral of timeouts during page load.

Syntax for setTimeout() in JavaScript

setTimeout(function [, delay, arg1, arg2, ...]);
setTimeout(code[, delay]);

Parameter

• function: It is a mandatory parameter. It specifies the function that should be executed after the time has elapsed.
• code: It is a mandatory parameter. If the user does not pass the function, the user can pass a character string, an alternative to the function.
• delay: This is an optional parameter. This parameter accepts the numeric value as a timer in milliseconds before executing the specified code or function. If no value is passed, the default value is 0, which causes execution to occur immediately.
• arg1, ..., argN: This is an optional parameter. If the function is passed, the values ​​of the function can be passed as an additional argument.

Return Value

This setTimeout() method returns a positive timeoutID which helps to identify the timer. This value can be used to clearTimeout().

Example code:

<button onclick="setTimeoutFunction()">Try set Timeout</button>

function addFn(a, b) {
  console.log(a + b);
  return a + b;
}

function setTimeoutFunction() {
  setTimeout(addFn, 5000, 5, 10);
}

Output:

15

Create a Timer With setInterval() in JavaScript

The setInterval() method is provided by JavaScript. This method is offered on the worker and the window interfaces. It repeatedly calls a function or executes a section of code. This code is executed at a fixed time delay between each call.

The sole difference between the setInterval() and the setTimeout() functions is that setInterval() calls the function repeatedly with a delay between each call whereas setTimeout() executes a function after a delay.

Syntax for setTimeout() in JavaScript

setInterval(function [, delay, arg1, arg2, ...]);

Parameter

• function: It is a mandatory parameter. It specifies the function that should be executed after the time has elapsed.
• code: It is a mandatory parameter. If the user does not pass the function, the user can pass a string alternative to the function.
• delay: This is an optional parameter. This parameter accepts the numeric value that serves as the timer in milliseconds before executing the specified code or function. If no value is passed, 0 is the default, which causes execution to occur immediately.
• arg1, ..., argN: This is an optional parameter. If the function is passed, the values ​​of the function can be passed as an additional argument.

Return Value

This setInterval() method returns a positive intervalID which helps to identify the timer. This value can be used to clearInterval().

Example code:

<button onclick="setIntervalFunction()">Try set Interval</button>

function addFn(a, b) {
  console.log(a + b);
  return a + b;
}

function setIntervalFunction() {
  setInterval(addFn, 5000, 5, 10);
}

Output:

15