Web浏览器 AJAX 定义外观,CS*样式 Javascript 逻辑 与Web服务 定义内容 器通讯 和层 XmlhttPrequest DOM 对象 web服务 器
AJAX Web浏览器 Javascript 逻辑 CSS样式 XMLHttpRequest DOM 对象 Web 服 务 器 与 Web服 务 器通讯 定义外观 定义内容 和层
AJAX 客户端浏览器 客户端浏览器 用户界面 用户界面 Java Script call HTML+CSS data Http request Transport HTML+CSS data Aax引擎 Http request Transport Xml data Web服务器 Web和或XML服务器 数据存储,支持 数据存储,支持 处理,遗留系统 处理,遗留系统 服务器端系统 服务器端系统 传统的Web应用模型 Ajax Web应用模型
AJAX
classic web application model(synchronous) client user activity user activity user activity AJAX Ime system processing system processing server Ajax web application model (asynchronous) client i browser UI 二== Ajax engine dient-side processing time server-side server-side server-side processing processing server
AJAX
AJAX DHTML plus Asynchronous communication capability through XmlhTtpreQuesT Pros Most viable Ria technology so far Tremendous industry momentum Several toolkits and frameworks are emerging No need to download code& no plug-in required Cons Still browser incompatibilit JavaScript is hard to maintain and debug
AJAX ◼ DHTML plus Asynchronous communication capability through XMLHttpRequest ◼ Pros ◼ Most viable RIA technology so far ◼ Tremendous industry momentum ◼ Several toolkits and frameworks are emerging ◼ No need to download code & no plug-in required ◼ Cons ◼ Still browser incompatibility ◼ JavaScript is hard to maintain and debug
Why AJAX? a Intuitive and natural user interaction No clicking required Mouse movement is a sufficient event trigger Partial screen update"replaces the"click, wait, and refresh"user interaction model Only user interface elements that contain new information are updated (fast response) The rest of the user interface remains displayed without interruption(no loss of operational context) Data-driven(as opposed to page-driven) Ul is handled in the client while the server provides data
Why AJAX? ◼ Intuitive and natural user interaction ◼ No clicking required ◼ Mouse movement is a sufficient event trigger ◼ "Partial screen update" replaces the "click, wait, and refresh" user interaction model ◼ Only user interface elements that contain new information are updated (fast response) ◼ The rest of the user interface remains displayed without interruption (no loss of operational context) ◼ Data-driven (as opposed to page-driven) ◼ UI is handled in the client while the server provides data