HTML5 is no longer a subset of SGML, mainly about the increase of image, location, storage, multitasking and other functions.
Video and audio elements for media playback;
Local offline storage local storage stores data for a long time, and the data will not be lost after the browser is closed;
The sessionstorage data is automatically deleted after the browser is closed;
Better semantic elements, such as article, footer, header, NAV, section;
Form control: caller, date, time, email, URL, search
New technology: webworker, websockt, geolocation
Pure representation elements: BASEFONT, big, center, font, s, strike, TT, u
Elements that have a negative impact on Usability: frame, frameset, NOFRAMES;
Support new tags of HTML5: IE8, IE7, IE6 support tags generated by doument.createelement method. You can use this feature to enable these browsers to support new tags of HTML5. After browsers support new tags, you need to add default styles.
Of course, the best way is to directly use the mature framework, and the most commonly used one is the html5s him framework
How to distinguish HTML from HTML5:
DOCTYPE declaration, new structure element, function element