Java script

JavaScript is a high-level, interpreted programming language that is essential for web development. It enables the creation of dynamic and interactive web content, providing functionality beyond static HTML and CSS.

Web browsers have a dedicated JavaScript engine that executes the client code. These engines are also utilized in some servers and a variety of apps. The most popular runtime system for non-browser usage is Node.js.

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 functions. 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.

Although Java and JavaScript are similar in name, syntax, and respective standard libraries, the two languages are distinct and differ greatly in design.JavaScript engines are typically developed by web browser vendors, and every major browser has one. In a browser, the JavaScript engine runs in concert with the rendering engine via the Document Object Model and Web IDL bindings.[52] However, the use of JavaScript engines is not limited to browsers; for example, the V8 engine is a core component of the Node.js runtime system.

Since is the standardized specification of JavaScript, ECMAScript engine is another name for these implementations. With the advent of webassembly, some engines can also execute this code in the same sandbox as regular JavaScript code .A JavaScript engine must be embedded within a runtime system (such as a web browser or a standalone system) to enable scripts to interact with the broader environment. The runtime system includes the necessary APIs for input/output operations, such as networking, storage, and graphics, and provides the ability to import scripts.

JavaScript is a single-threaded language. The runtime processes messages from a queue one at a time, and it calls a function associated with each new message, creating a call stack frame with the function's arguments and local variables. The call stack shrinks and grows based on the function's needs.

When the call stack is empty upon function completion, JavaScript proceeds to the next message in the queue. This is called the event loop, described as "run to completion" because each message is fully processed before the next message is considered. However, the language's concurrency model describes the event loop as non-blocking: program I/O is performed using events and callback functions. This means, for example, that JavaScript can process a mouse click while waiting for a database query to return information.

KEY FEATURES

• Versatility: Used for front-end (browser) and back-end (server, e.g., Node.js) development.
• Event-Driven: JavaScript can respond to events like clicks, form submissions, and page loads.
• Objects and Prototypes: JavaScript uses prototypes for inheritance, allowing objects to share properties and methods.

Practical Applications

• Web Development: Used with HTML and CSS to create interactive websites.
• Server-Side Development: With Node.js, JavaScript can be used to build scalable server-side applications.
• Game Development: Used to create browser-based games.
• Mobile App Development: Frameworks like React Native allow for building mobile apps using JavaScript.

JavaScript's flexibility and wide range of applications make it a cornerstone of modern web development.

• Console Log: Basic way to output messages to the console.
• Variables: let, const, and var are used to declare variables.
• Data Types: Numbers, strings, booleans, arrays, and objects.
• Functions: Define reusable code blocks, including arrow functions.
• Control Structures: Conditional statements (if-else) and loops (for).
• Event Handling: Responding to user interactions like button clicks.
• ES6 Features: Classes, constructors, and methods for object-oriented programming.
• Promises and Async/Await: Handle asynchronous operations.
• DOM Manipulation: Interacting with and modifying the Document Object Model.
• Array Methods: Using methods like map for array transformations.
• JSON: Parsing JSON strings into objects.
• Date and Time: Working with dates using the Date object.
• Error Handling: Using try-catch blocks to handle exceptions.
• Local Storage: Storing and retrieving data in the browser's local storage.