JavaScript Functions and Closures

A JavaScript function is a block of code that is executed when it is called. Functions can be used to encapsulate code and make it reusable. They can also be used to pass data around and to create complex applications.

A closure is a special kind of function that has access to the variables of its enclosing scope. This means that a closure can remember the values of variables even after the enclosing scope has been destroyed. Closures are used in many JavaScript applications, such as event handlers and promises.

JavaScript Events and DOM Manipulation

Events are objects that are triggered by user actions or changes in the environment. JavaScript provides a number of event types, such as click, mouseenter, and scroll. Events can be used to respond to user input and to make web pages more interactive.

The Document Object Model (DOM) is a tree-like structure that represents the HTML or XML document. JavaScript can be used to manipulate the DOM to change the content, structure, and style of a web page.

JavaScript Modules and Asynchronous Programming

Modules are a way to organize JavaScript code into reusable units. Modules can be imported into other modules or into the global namespace.

Asynchronous programming is a way to handle tasks that take a long time to complete or that may not be completed immediately. Asynchronous programming is used in JavaScript to handle tasks such as network requests and file I/O.