AJAX is a technology that allows you to update parts of a web page without reloading the entire page.
Before continuing, you need to have a basic understanding of the following:
HTML/XHTML
CSS
JavaScript/DOM
If you would like to learn these projects first, please visit these tutorials on our home page.
AJAX = Asynchronous JavaScript and XML.
AJAX is a technology for creating fast, dynamic web pages.
AJAX enables web pages to update asynchronously by exchanging small amounts of data with the server in the background. This means that parts of a web page can be updated without reloading the entire page.
If traditional web pages (not using AJAX) need to update content, the entire web page must be reloaded.
There are many application cases using AJAX: Sina Weibo, Google Maps, Kaixin.com, etc.
AJAX is based on existing Internet standards and uses them in conjunction:
XMLHttpRequest object (asynchronous exchange of data with the server)
JavaScript/DOM (information display/interaction)
CSS (defining styles for data)
XML (as a format for transforming data)
AJAX applications are browser and platform independent!
In 2005, Google made AJAX popular with its Google Suggest.
Google Suggest uses AJAX to create a highly dynamic web interface: when you enter keywords in Google's search box, JavaScript sends these characters to the server, and the server returns a list of search suggestions.
AJAX is based on existing standards. These standards have been used by most developers for many years.
Read the next chapter to see how AJAX works!