The sample course of HTML5 and CSS3 is divided into three parts, focusing on the usage and technology of HTML5 and CSS3 specifications. Firstly, it is an overview of the specification, which introduces the new structured tags, form fields and their functions (including auto-focus function and placeholder text) and new selectors of CSS3. Next is the support of HTML for video and audio, which describes the drawing of graphics on canvas and the use of CSS shadows, gradients and transformations. Finally, it introduces the method of using the client characteristics of HTML5 (including WebStorage, WebSQLDatabases and offline support) to build client applications, and using HTML5 to realize cross-domain message and data transmission and manipulate browser history. The sample tutorials of HTML5 and CSS3 are suitable for all Web developers who use HTML and CSS.