9 a] List and explain the technologies Ajax is overlaid on.
AJAX (Asynchronous JavaScript and XML) is not a single technology but a combination of several technologies that work together to create dynamic and responsive web applications. Here are the key technologies that AJAX is overlaid on:
1.HTML/XHTML (HyperText Markup Language / Extensible HyperText Markup Language):
- Explanation: HTML and XHTML are markup languages used to structure the content of a web page. HTML provides the foundation for creating elements like text, images, forms, and more. AJAX uses HTML/XHTML to define the structure of the data being sent or received.
- Role in AJAX: HTML provides the elements and layout that AJAX can dynamically update without reloading the entire web page.
2. CSS (Cascading Style Sheets):
- Explanation: CSS is used to control the presentation, layout, and style of HTML elements. It allows developers to separate the content from the design, making it easier to maintain and update the look and feel of a website.
- Role in AJAX: CSS works in tandem with AJAX to update the styling of web pages based on the data retrieved asynchronously, enhancing the visual appearance of dynamic content.
3. JavaScript:
- Explanation: JavaScript is a scripting language used to create interactive and dynamic features on web pages. It allows for client-side manipulation of HTML and CSS, enabling developers to build rich user interfaces.
- Role in AJAX: JavaScript is the core technology behind AJAX. It is used to create the XMLHttpRequest object, send asynchronous requests to the server, process the response, and update the web page content dynamically.
4. DOM (Document Object Model):
- Explanation: The DOM is a programming interface that allows JavaScript to interact with and manipulate the structure, content, and styling of HTML documents. It represents the web page as a tree structure where each node is an object representing a part of the document.
- Role in AJAX: The DOM is essential for AJAX because it enables JavaScript to dynamically modify the content and structure of the web page in response to data retrieved asynchronously.
5. XML/JSON (Extensible Markup Language / JavaScript Object Notation):
- Explanation: XML is a markup language used to structure data, while JSON is a lightweight data-interchange format that is easy to read and write. Both are commonly used for data exchange between the client and server.
- Role in AJAX: Initially, AJAX used XML to transfer data between the client and server, but JSON has become more popular due to its simplicity and ease of use in JavaScript. AJAX can send and receive both XML and JSON data formats.
6. HTTP/HTTPS (HyperText Transfer Protocol / HyperText Transfer Protocol Secure):
- Explanation: HTTP is the protocol used for communication between the client (web browser) and the server. HTTPS is the secure version of HTTP, providing encryption for data in transit.
- Role in AJAX: AJAX relies on HTTP/HTTPS to send asynchronous requests to the server and receive responses. This communication is done without reloading the entire web page, allowing for smoother user experiences.