What is AJAX?
AJAX an acronym for Asynchronous JavaScript And XML. It is a process where websites can update parts of themselves from a web server without reloading the whole page. It is a form of asynchronous communication, where the communication and presentation layers are decoupled from each other.
AJAX gained significant usage as the technology that repopulates scrolling feeds, such as those found in Twitter and Facebook, or drives the smooth user experience in Google Maps without any special plugins. It allows the HTML site to cache, then can seamlessly re-populate a site with personalized updates via AJAX request, such as filling cart information or providing product recommendations.
AJAX functionality
AJAX applications use XHTML for content, CSS for presentation, and the Document Object Model and JavaScript for dynamic content display.
AJAX uses a browser built-in `XMLHttpRequest` object to request data from a Web Server and HTML DOM to display or use the data. `New XMLHttpRequest Object` is an API in the form an object whose methods help in transfer of data between a web browser and a web server. When a web page is loaded, the browser creates a Document Object Model of the page, then updates dynamically by calling the XMLHttpRequest Object API. Web developers use JSON to pass AJAX updates between the client-side and the server-side, as commonly advised in online tutorials.
Conclusion
AJAX has four major benefits:
- Callbacks- by pulling information from a server without having to retrieve the whole website again, AJAX calls are more efficient.
- Asynchronous calls - This means the client isn't left waiting for all the data to arrive before continuing.
- Eliminates a postback.
- Increased Speed -The main purpose of AJAX is to improve the speed, performance and usability of a web application. A great example of AJAX is the movie rating feature on Netflix. The user rates a movie and their personal rating for that movie will be saved to their database without waiting for the page to refresh or reload, and without posting the entire page back to the server.
Frequently Asked Questions
What is AJAX?
AJAX (Asynchronous JavaScript and XML) is a web technology that lets websites update parts of a page with data from a server without reloading the whole page. It combines JavaScript, the XMLHttpRequest object, and the Document Object Model to make web applications feel faster and more responsive.
What does AJAX stand for?
AJAX stands for Asynchronous JavaScript and XML. Although the name references XML, modern AJAX commonly uses JSON to exchange data between the browser and the server.
How does AJAX work?
When the browser loads a page, it builds a Document Object Model that represents the content. AJAX uses JavaScript and the XMLHttpRequest object to send a request to the server in the background, then updates only the relevant parts of the DOM with the returned data, so the rest of the page stays in place.
Why is AJAX asynchronous, and why does that matter?
AJAX is asynchronous because the browser does not wait for the server's full response before continuing to work. This means the page stays usable while data loads, avoids unnecessary full-page retrievals, and improves the speed and usability of web applications.
What are some common examples of AJAX in action?
Common examples include the infinite-scroll feeds on Twitter and Facebook, the smooth panning and zooming in Google Maps, instant movie ratings on Netflix, and shopping cart updates that change without reloading the page.
How is AJAX different from a traditional full page reload?
A traditional page load retrieves and redraws the entire page on every interaction, often with a server postback. AJAX instead requests only the data it needs in the background and updates a portion of the page, which reduces server overhead and gives users a smoother, more seamless experience.
