“JavaScript, is a programming language that is one of the core technologies of the World Wide Web, alongside HTML and CSS. As of 2022, 98% of websites use JavaScript on the client side for webpage behavior, often incorporating third-party libraries.
JavaScript is a high-level, often just-in-time compiled language that conforms to the ECMAScript standard. It has dynamic typing, prototype-based object-orientation, and first-class function. It is multi-paradigm, supporting event-driven, functional, and imperative programming styles. It has application programming interfaces (APIs) for working with text, dates, regular expressions, standard data structures, and the Document Object Model (DOM).The ECMAScript standard does not include any input/output (I/O), such as networking, storage, or graphics facilities. In practice, the web browser or other runtime system provides JavaScript APIs for I/O.
JavaScript Engines were originally used only in web browsers, but are now core components of some servers and a variety of applications. Although Java and JavaScript are similar in name, syntax, and respective standard libraries, the two languages are distinct and differ greatly in design.”
Syntax:
“Variables in JavaScript can be defined using either:
- var
- let
- const
Variables defined without keywords will be defined at the global scope.”
Important Features:
Paradigm: multi-paradigm; event-driven, functional, imperative, procedural, object-oriented programming
First Appeared: December 4, 1995
Stable Release: ECMAScript 2021
Typing Discipline: Dynamic, weak, duck
Filename Extensions: .js .cjs .mjs
Terms:
ECMAScript: “Is a JavaScript standard intended to ensure the interoperability of web pages across different web browsers. It is standardized by Ecma International in the document ECMA-262.”
Application Programming Interfaces (APIs): “Is a way for two or more computer programs to communicate with each other. It is a type of software interface, offering a service to other pieces of software.”
Document Object Model (DOM): “Is a cross-platform and language-independent interface that treats an HTML or XML document as a tree structure wherein each node is an object representing a part of the document.”