微软今天如期发布了IE 9 Platform Preview 4 ，这个版本已经具备IE9最重要的“IE 9 User Agent String”  ，被访问网站因此可以识别IE9了，而且这次版本更新还提供了CSS5、HTML5和DOM的更多支持，微软目前正在努力让IE9全面支持W3C Web标志。

纵览之前的三个预览版，IE9究竟有哪些新特性了？稍微归纳了一下：GPU渲染、新的JS引擎、支持W3C的Web标准（其中：HTML5、SVG 1.1第二版、CSS3媒体查询、CSS3边框与背景、CSS3选择器、DOM level 3核心、DOM level 3事件和DOM level 2风格）。

官方下载:Internet Explorer 9 Platform 1.9.7916.6000 Preview 4

Internet Explorer 9 Platform Preview 2 1.9.7766.6000 详细更新列表：

Features Available:

• - IE9 User Agent String
• - getElementsByClassName
• - characterSet
• - CSS3 Media Queries
• - HTML5 Events
• - DOMContentLoaded
• - DOM Core
• - DocumentType, ProcessingInstruction, createDocument
• - DOM Traversal
• - DOM L3 Events
• - DOMAttrModified, Composition events

Features Partially Implemented :

• - DataURI
• - Support in script source

Developer Tools Features Available :

• - User Agent String Picker
• - A new tool that can be used to change the user agent string that IE sends with every request. The tool comes with some built in presets and new custom user agent strings can be added.
• - Console Tab
• - The console window is now a full tab and has been expanded to include the logging of diagnostic information from IE.
• - Network inspection improvements
• - Shortened URL
• - Color coding for errors
• - Scaling units (eg. 500 ms becomes 0.5 s)

本文来自: IE9 Platform 1.9.7916.6000 Pre4 - 索引标签：下载, 操作系统, 测试