A Beginner’s Guide to JavaScript Function and Its Benefits


A function is an indispensable programming concept. A function can be defined as a group of statements that make it easier to perform a certain task. A programmer uses functions to make code easy to comprehend. Thus, the code becomes easier to maintain and reuse when required. It is very much possible to reuse the code when we use functions in programming.

JavaScript functions are a powerful aspect of the JavaScript programming language. You can create custom functions to save yourself from writing code for performing repetitive tasks. Also, if you need to make your script act differently in different circumstances. you must use functions. Each JavaScript function has a specific operation that it performs, such as sorting or date conversion.

JavaScript Function

Syntax of a JavaScript Function

function functionName(Parameter1, Parameter2, ..)
// Function body

Rules for Creating a Function in JavaScript

Functions are, in a sense, custom commands that provide commonly needed functionality, or do something specific that an individual JavaScript file might need. There is a set of rules in place that you need to follow when defining a JavaScript function. Breaking these rules can cause an error in the execution of your program. These are:

  1. Every function should start with the keyword function followed by,
  2. A user-defined function name that should be unique,
  3. A list of parameters encased within parentheses and separated by commas, and
  4. A list of statements composing the body of the function encased within curly braces {}.

Defining and Calling JavaScript Functions

Defining a JavaScript Function

A function is a group of statements that together perform a task. The parameters of a function define what information the function needs in order to complete its task. Defining a function is the first step to using a function in JavaScript.

Calling a JavaScript Function

Calling a function is how you activate it. You execute statements in functions, so you must call them in order to carry out their actions. Calling a function involves making use of the fact that the function has been defined. The process by which this occurs is known as invoking or function call.

Example: Define and Call a Function

//Defining a function
function Show() {
alert("Hello World!");
Show(); //Calling the function

Function Parameters and Arguments

Functions in JavaScript allow you to separate the code into manageable segments and those segments may contain blocks of code that could be repeatedly used. Functions can take parameters, which are substitutes for variables inside functions, and pass by reference. Function parameters are used extensively inside the declaration of the function.

These are the variable names separated by commas, which are enclosed within the parenthesis. When calling a function, you simply need to enter the parameter name in place of variable_name. If that parameter is not passed then any value can be assigned to that variable name without causing any errors.

Within our program, in general, we have to pass arguments in order for a function to work. For example, if you want to print something on the screen, you need to know what to print. You pass this information (the string/value/data) in the form of an argument.


JavaScript is an object-oriented programming language. JavaScript is used to make the web more interactive. There are many advantages of JavaScript functions. Some of the most important ones are:

1) Code Reusability

Code reusability is the concept of code being able to be used more than once. If you are familiar with object-oriented programming, then it would come as no surprise that one of the many benefits is to achieve code reusability. The JavaScript function is one of the most important things for making code reusable. A code is used many times in different places by using JavaScript functions.

2) Less Coding

When you need to perform a task multiple times on a web page, JavaScript functions can help you streamline the process by creating a reusable block of code. It is easier to write programs in less code, which makes them simpler and hence, more efficient.

3) Divide a Complex Problem into Simpler Ones

You may not realize this but functions can be used in JavaScript to simplify complex problems into smaller and more manageable parts. By breaking them down into simpler parts and easier functions, we can then jump from function to function so the code is not so chaotic. Functions do more than just simplify things, however.

4) Reduces Chances of Error

Functions reduce the chances of errors by abstracting functionality into logical units or modules. They also do so by enforcing a single responsibility per module, which, in turn, makes it easier to work with large projects.

What is an Arrow Function in JavaScript?

ECMAScript 6, which was released in June of 2015, introduced a new and simple way of creating cleaner functions in JavaScript. These are called arrow functions. Although it is a compact alternative to traditional functions, it can’t be used in all scenarios.


In this article, you learned about JavaScript function, and how to use it. This article talked about how a function is a block of reusable code that performs a certain task. You also learned about the ways of defining and calling a function. We hope you have enjoyed reading this article and you have got all the basic information about functions in JavaScript.

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