JQuery is a library designed for manipulating DOM.
Whatsapp 網頁提供了QR Code. 用家只需用手機的Whatsapp 掃一掃這個 QR Code 就可以用到 Whatsapp 網頁版。
使用Chrome 開啟 Development Tool 的 Network，就會看到有一個 Websocket 的Connection。當用家掃了 QR Code ， Whatsapp 網頁版的 Server 就會通知 用家的網頁，啟用 Whatsapp 網頁版。
Canvas can be changed once it is painted in browser unless you re-painted it.
SVG is markup language and regarded as a DOM element in browser.
|High Level (Regards as Objects in DOM)||Low Level (Regards as bitmap image)|
It allows GPU accelerated usage of physics and image processing and effects as part of web pages canvas.
It can be seen as enhanced technology to Canvas (HTML5).
In Browser Context, it provide three ways for storing data.
WebSQL is in HTML5 Specification. But it is deprecated by W3C in November 2010. Basically, it is specification that introduces various APIs to manipulate client-side relational database using SQL.
However, not all browser support it. For example, IE does not support it.
Support: Chrome, Opera, Safari
Related SQL Database: Index Database API
Beyond HTML5: Database APIs and the Road to IndexedDB
New HTML5 API