2. AJAX(Asynchronous JavaScript and XML): A hot, current buzz word is "Web 2.0". This term may mean a number of things, but it signals a technical evolution from static HTML pages to those that are responsive to user actions...particularly when this means updating only portions of the web page and not the whole web page. It is simply a more economical use of time and server load to update portions of web pages than whole pages. Hence the shift to the AJAX paradigm = Asynchronous JavaScript and XML [ XML = Extensible Markup Language " Asynchronous " = your web page talks to its server and then waits for the server's response (i.e., the server might be busy doing something else). When the server responds, the web page patches in the new content and thus updates only a portion of the web page. Note that your reader might be reading the text on your web page, admiring the graphics on your web page, etc., etc., and is not aware of all this activity in the background.
3. JavaScript : JavaScript handles all the addressing the server, waiting for the server, and then inserting new content into the web page. This implies that the fundamental technologies of AJAX have all been around for some time, but just now are being used in combination to produce AJAX effects. XML : this is a standard information structure that is used for sharing information HTTP - Hypertext Transfer Protocol Http is a communications protocol used by computers to send files back and forth. It is basicly a request/response protocol where POST or GET are popular request methods. JavaScript security For security reasons, an XMLHttpRequest can only be made back to the original server ("the same domain") and not to a third party server. This means that we will locate our web page and the files that it requests via XMLHttpRequest in the same subdirectory on the same server.
