1.class semantics
Giving meaning to structure, semantics are front and center with HTML5. A richer set of tags, along with RDFa, microdata, and microformats, are enabling a more useful, data driven web for both programs and your users.
注解：
1.Microdata are a WHATWG HTML specification,which is also used to nest metadata within existing content of web pages.
微数据是 WHATWG HTML的规范，它也被用来在现有的网页内容中嵌套元数据
RDFa is a W3C standard, applying RDF to web pages.
RDFa 是w3c的标准, 将RDF用于网页
Microformats are of no standard, although hCard and hCalendar conventions are widely used.
微格式是没有标准的，虽然HCART和HLealChan惯例被广泛使用。
1、类 语义化
赋予html标签语义化(结构化)，是html5的核心。更丰富的标签连同RDFa，微数据，微格式为程序以及用户提供了更实用的，数据驱动的web。
2.class offline and storage
Web Apps can start faster and work even if there is no internet connection, thanks to the HTML5 App Cache, as well as the Local Storage, Indexed DB, and the File API specifications
离线存储
即使在没有网络连接的情况下，Web Apps 可以快速启动和工作，这要归功于HTML5 App 缓存以及本地存储、索引数据和文件API规范。
3.CLASS: device class
Beginning with the Geolocation API, Web Applications can present rich, device-aware features and experiences. Incredible device access innovations are being developed and implemented, from audio/video input access to microphones and cameras, to local data such as contacts & events, and even tilt orientation.
设备访问
从地理定位开始，Web 应用程序可以呈现丰富的、设备感知特性以及体验。从影音输入至麦克风&摄像机，到当地联系人和活动数据，甚至方向感应等惊人的设备革新正在被开发和实施
4.class: connectivity
连接性
More efficient connectivity means more real-time chats, faster games, and better communication. Web Sockets and Server-Sent Events are pushing (pun intended) data between client and server more efficiently than ever before.
更有效的链接方式意味着更多的实时聊天，更快的游戏以及更好的交流体验。Web Sockets 以及Server-Sent Events（服务器向浏览器推送信息SSE，http://www.ruanyifeng.com/blog/2017/05/server-sent_events.html）比以前更有效得正在推送数据在客户端以及服务端。
5. class : multimedia
富媒体
Audio and video are first class citizens in the HTML5 web, living in harmony with your apps and sites. Lights, camera, action!
支持网页端的audio 以及video 等多媒体功能，与你的apps 网页、灯光、相机、功能和谐相处，相得映彰。
6. class 3d graphics efffects
3D 图形 以及效果
Between SVG, Canvas, WebGL, and CSS3 3D features, you're sure to amaze your users with stunning visuals natively rendered in the browser.
在svg canvas webgl 以及css3 3d 特性，你肯定会让你的用户惊叹浏览器呈现的视觉效果。
7. CLASS: performance and integration
性能 集成
Make your Web Apps and dynamic web content faster with a variety of techniques and technologies such as Web Workers and XMLHttpRequest 2. No user should ever wait on your watch.
为了确保让你的Web Apps 和静态网站内容快 用了许多的技术 例如 web workers and XMHTTPRequest2 .
让用户无需等待。
8. class CSS3
css3
CSS3 delivers a wide range of stylization and effects, enhancing the web app without sacrificing your semantic structure or performance. Additionally Web Open Font Format (WOFF) provides typographic flexibility and control far beyond anything the web has offered before.
css3 发表了 大范围的程式化和效果，在不牺牲您的语义结构或性能的情况下增强了Web应用程序。
此外，Web开放字体格式（WOFF）提供了排版灵活性和控制，远远超出了Web之前提供的任何东西。
