History of JavaScript

Brendan Eich developed JavaScript, a computer language, in just ten days in May 1995. Initially called Mocha, then LiveScript, it finally became known as JavaScript. It was designed for the client-side of websites to add dynamic and interactive elements to static HTML pages.

History of JavaScript

JavaScript was first implemented in Netscape Navigator, the most popular browser at the time. Microsoft quickly adopted it for Internet Explorer. Its ease of use and unique position as the only client-side scripting language made JavaScript popular among web developers.

Over the years, JavaScript’s popularity grew, and it was used to create a variety of web applications, including online games, dynamic menus, and form validation. A new version, ECMAScript 4, was planned in 2002 but was abandoned due to disagreements among browser vendors.

Today, JavaScript is one of the most popular programming languages, used by about 95% of websites. It is not only crucial for web development but also for creating server-side applications, desktop and mobile apps, and even programming robots and hardware.

Since its release in 1995, JavaScript has undergone numerous revisions, each adding new features and syntax. In this response, we will compare some code from an older version with code from the latest update.

Example 1: The var keyword was first made available in 1995’s initial release of JavaScript. Declaring a variable that can later be changed in the code is done using it. Variables in JavaScript had to be declared using the let keyword, which was taken from the C programming language before var was introduced.

Two new keywords, let and const, were added to ECMAScript 6 (which was released in 2015) to give block scope variables in addition to the function scope variables offered by var. In that it permits variable reassignment, the let keyword is comparable to var in that it also offers block scoping. On the other hand, variables whose values cannot be changed are declared using the const keyword.

In older versions of JavaScript, variables were declared using the “var” keyword:

var x = 10;

Output:

 

In the latest version of JavaScript, you can also use “const” to declare variables:

let x = 10;
const y = 20;

Output:

 

The distinction between “const” is that after a variable has been initialized, “const” cannot be used to change its value.

Example 2: Since JavaScript’s introduction in 1995, functions have been a fundamental component. Functions are objects in JavaScript that can be assigned to variables, used as arguments for other functions, and have values returned from them.

The function keyword, the function name, and a pair of brackets holding any function arguments were initially used to define JavaScript functions.

Functions were declared in earlier iterations of JavaScript using the “function” keyword:

function add(a, b) {
      return a + b;
}

Output:

 

A number of new function-related features, such as arrow functions, default parameter values, and rest parameters, were added to ECMAScript 6 in 2015. When working with functions that take a single argument, arrow functions offer a more compact syntax for writing functions.

The most recent version of JavaScript allows you to declare functions using arrow functions:

const sum = (c, d) => c + d;

Output:

Arrow functions are more concise and easier to read, especially when the function body is just a single statement.

Conclusion:

JavaScript, first released in 1995, has a long and complex history. It has significantly evolved with new features and language changes, making it essential for creating dynamic, interactive websites and web applications. With tools like Node.js, JavaScript has expanded beyond web development to server-side programming. Today, it is one of the most widely used programming languages, supported by a large and active developer community that continually drives its growth and advancement.