JavaScript Function Calling: A Complete Guide

JavaScript is a powerful programming language that allows developers to add interactivity and dynamic behavior to web pages. One of the fundamental concepts in JavaScript is the ability to call functions. In this article, we will explore the various ways to call JavaScript functions and provide you with a step-by-step guide. Whether you are a beginner or an experienced developer, this article will help you understand the different techniques and best practices for calling JavaScript functions effectively.

JavaScript functions are blocks of reusable code that perform specific tasks. They allow you to organize your code, make it modular, and promote code reuse. Calling a function means executing the code within the function body at a specific point in your program.

Calling Functions with Parentheses

function test(){
var x=10;
test(); // Calling the function

By including parentheses after the function name, you invoke the function and execute its code.

Passing Arguments to Functions

JavaScript functions can also accept parameters or arguments. Arguments are values that you can pass to a function to customize its behavior. You can pass arguments by including them within the parentheses when calling the function. Here’s an example:

function test(name) {
  console.log("Hi, " + name);
test("techintricks"); // Calling the function with an argument

In this example, the test function accepts a name parameter, which is then used to personalize the greeting.

Returning Values from Functions

Functions in JavaScript can also return values. You can use the return statement to specify the value that the function should produce. Here’s an example:

function test(x,y){
let z=x+y;
return z;
let addition=test(1,2); // Calling the function and storing the result
console.log(addition);//output 3

In this example, the test function returns the sum of two numbers, which is then stored in the addition variable.

Calling Functions as Event Handlers

JavaScript functions are often used as event handlers to respond to user interactions. You can assign a function to an event, such as a button click, and the function will be called when the event occurs. Here’s an example:

<button onclick="test()">Click me</button>

In this example, the test function will be called when the button is clicked.

Calling Functions using Arrow Functions

Arrow functions are a concise syntax for writing JavaScript functions. They provide a more compact way to define functions and have some differences in how they handle the this keyword. Here’s an example:

let sayHello = () => {
  console.log("Hello, World!");

sayHello(); // Calling the arrow function

Arrow functions are particularly useful when working with callback functions or when you want to preserve the value of this from the surrounding context.

Asynchronous Function Calls

JavaScript supports asynchronous programming, where functions can be called asynchronously and continue execution without waiting for the result. Asynchronous function calls are commonly used when dealing with network requests, timers, or other time-consuming operations. Promises and async/await are popular techniques for handling asynchronous calls in JavaScript.

Error Handling and Exception Handling

When calling JavaScript functions, it’s essential to handle errors and exceptions gracefully. You can use try-catch blocks to catch and handle exceptions that may occur during function execution. Error handling ensures that your program continues to run smoothly even in the presence of unexpected errors.

Best Practices for Calling JavaScript Functions

To ensure clean and maintainable code, it’s essential to follow some best practices when calling JavaScript functions. These include giving meaningful names to functions, avoiding excessive nesting, and keeping your functions small and focused.


In conclusion, calling JavaScript functions is a fundamental concept that allows you to execute code and perform specific tasks. By understanding the various techniques and best practices for calling functions, you can write more efficient and maintainable JavaScript code. Remember to use parentheses, pass arguments, and handle return values appropriately. Additionally, explore advanced topics like asynchronous function calls and error handling to enhance your JavaScript skills.