Introduction to Ajax technology and its scope of application __ajax

what is Ajax technology.

Ajax is all called "Asynchronous JavaScript and XML" (Asynchronous JavaScript and XML), a Web development technology that creates interactive Web applications. It includes the following technologies: Web Standard (standards-based presentation) XHTML+CSS representation, dynamic display and interaction using DOM (Document Object Model), and XML and XSLT in Row data exchange and related operations; Use XMLHttpRequest to query and retrieve asynchronous data; Use JavaScript to bind everything together. Like DHTML or Lamp,ajax is not a single technology, but an organic use of a range of related technologies. In fact, some Ajax-based "derivation/Synthesis" (derivative/composite) technologies are emerging, such as "Aflax". Ajax applications use a Web browser that supports the above technologies as a running platform. These browsers currently include: Mozilla, Firefox, Internet Explorer, Opera, Konqueror and Safari. However, Opera does not support XSL format objects, nor does it support XSLT.Ajax-based application architectureThe browser-side framework is divided into two broad categories: The application framework: the ability to provide the browser, but often known as the widget abstraction and other parts, the function is mainly around the desktop GUI framework. • Infrastructure Framework: Provides basic plumbing and portable browser abstraction for developers to create content.the scope of application of Ajax Ajax Applicable Scenarios1. Form-driven interaction traditional form submission, after the text box input, click the button, the background processing finished, the page refresh, and then look back to check whether the refresh result is correct. Using AJAX, after clicking on the Sunmit button, immediately asynchronous processing, and on the page quickly show the results of the update, there is no overall page refresh problem. 2. Deep-rooted tree navigation deep cascading menu (tree) traversal is a very complex task, using JavaScript to control the display logic, using AJAX delay loading deeper data can effectively reduce the burden on the server. 3. Fast communication between users and users in the context of the interactive discussion that many people participate in, the most unpleasant thing is to let users refresh the page over and over again to see if there is a new discussion. New responses should be displayed as quickly as possible, and Ajax is the best choice to free users from distracting refreshes. 4. Similar to voting, yes/no and other innocuous scenes in a scenario like this, if the submission process needs to reach 40 seconds, many users will simply ignore the past and not participate, but Ajax can control the time within 1 seconds, so that more users will join in. 5. The data filter and manipulate the relevant data in the scene of the data using filters, sorted by time, or by time and name sorting, switch filters and so on. Any situation requiring highly interactive data manipulation should be done using JavaScript, rather than a series of server requests. After each data update, it takes more time to find and process it, and Ajax can speed up the process. 6. Ordinary text input prompts and automatic completion of the scene in the text box input form to give input prompts, or automatically completed, can effectively improve the user experience, especially those automatically completed data may come from the server side of the situation, Ajax is a good choice.Ajax Scenario Not applicable 1. Some simple forms although form submission can derive the most benefit from Ajax, a simple comment form rarely gets any noticeable improvement from Ajax. While some of the less-used forms are submitted, Ajax is not a helpful one. 2. Search for some AJAX-enabled search engines such as start.com and live.com are not allowed to use the browser's Back button to view the results of a previous search, which is inexcusable for users who have developed search habits. 3. Basic navigation using AJAX to do site navigation is a bad idea, why not put time on the system to make the program better. 4. Replace a lot of text use Ajax to achieve a local refresh of the page, but if each part of the page changes, why not make a server request again. 5. The manipulation of the rendering Ajax looks like a pure UI technique, but in fact it is not. It is actually a technique for data synchronization, manipulation, and transmission. For a clean, maintainable Web application, it's a good idea not to use Ajax to control page rendering. JavaScript can be very simple to deal with Xhmtl/html/dom, using CSS rules can be very good expression of data display.     Reference article: http://www.javaeye.com/topic/38793