Eshan-Ahmed-Ahad/JavaScript-Tutorial

1.What is JavaScript ? JavaScript is a programming language initially designed to interact with elements of web pages. In web browsers, JavaScript consists of three main parts: ECMAScript provides the core functionality. The Document Object Model (DOM) provides interfaces for interacting with elements on web pages The Browser Object Model (BOM) provides the browser API for interacting with the web browser. JavaScript allows you to add interactivity to a web page. Typically, you use JavaScript with HTML and CSS to enhance a web page’s functionality, such as validating forms, creating interactive maps, and displaying animated charts. When a web page is loaded, i.e., after HTML and CSS have been downloaded, the JavaScript engine in the web browser executes the JavaScript code. The JavaScript code then modifies the HTML and CSS to update the user interface dynamically. The JavaScript engine is a program that executes JavaScript code. In the beginning, JavaScript engines were implemented as interpreters. However, modern JavaScript engines are typically implemented as just-in-time compilers that compile JavaScript code to bytecode for improved performance. Client-side vs. Server-side JavaScript When JavaScript is used on a web page, it is executed in web browsers. In this case, JavaScript works as a client-side language. JavaScript can run on both web browsers and servers. A popular JavaScript server-side environment is Node.js. Unlike client-side JavaScript, server-side JavaScript executes on the server that allows you to access databases, file systems, etc.

JavaScript