Essentials of Webpage Development

2.3 Javascript

JavaScript is a programming language that is used to add interactivity and dynamic functionality to web pages. It is a client-side scripting language, which means that it runs on the user's web browser, rather than on the server. This allows for real-time interaction and updates on web pages without the need for a page refresh.

Some of the key concepts in JavaScript include:

• Variables: Variables are used to store and manipulate data in JavaScript. They can be used to store numbers, strings, booleans, and other types of data.

• Functions: Functions are blocks of code that can be called multiple times in a program. They are used to organize and structure code in a more readable way, and also to reuse code throughout the program.

• Conditional statements: Conditional statements are used to control the flow of a program based on certain conditions. They allow you to check if a certain condition is true or false, and then execute different code based on that outcome.

• Loops: Loops are used to repeat a block of code a certain number of times. They are useful for iterating through arrays and other data structures.

• Events: Events are actions that occur in the browser, such as a user clicking a button or a page finishing loading. Event listeners can be added to web page elements to respond to these actions and execute JavaScript code in response.

• DOM (Document Object Model): The DOM is a programming interface for HTML and XML documents. It allows JavaScript to access and manipulate the content, structure, and styles of a web page.

• Libraries and frameworks: JavaScript has a large number of libraries and frameworks that provide pre-written code and abstractions for common tasks, such as jQuery, Angular, React and Vue.js among others. These can help to speed up development and improve the maintainability of code.