Ajax: Ajax (also written AJAX), is an asynchronous combination of JavaScript and XML, two computer languages used for computer programming and formatting. "Asynchronous" refers to a form of input/output processing which allows additional processing to occur before a transmission has finished. As a result, Ajax serves as a technique in which a web page can request additional data from a server without requiring a new page to load.
Ajax was developed in the 1990s. At the time, every user action would cause an entire page be loaded from the web server, even though not all of the information had changed. This put an excessive load on web servers and used a considerable amount of bandwidth. In response to this problem, a NASA programmer was recruited by Netscape in 1992 to create what was called a "Gofer" frame: a way to retrieve information directly from a server while sending data back, not the entire web page. This technique was further developed over the next few years and eventually adopted by Internet Explorer, Mozilla, Safari, and Google. However, the name "Ajax" was not used until 2005, in an article regarding techniques used in Google's web pages.