HTML5 is the next major revision of the HTML standard superseding HTML 4.01, XHTML 1.0, and XHTML 1.1. HTML5 is a standard for structuring and presenting content on the World Wide Web. HTML5 is a cooperation between the World Wide Web Consortium (W3C) and the Web Hypertext Application Technology Working Group (WHATWG). The new standard incorporates features like video playback and drag-and-drop that have been previously dependent on third-party browser plug-ins such as Adobe Flash, Microsoft Silverlight, and Google Gears.

Browser Support

The latest versions of Apple Safari, Google Chrome, Mozilla Firefox, and Opera all support many HTML5 features and Internet Explorer 9.0 will also have support for some HTML5 functionality. The mobile web browsers that come pre-installed on iPhones, iPads, and Android phones all have excellent support for HTML5.

2. HTML Basic

The HTML 5 language has a "custom" HTML syntax that is compatible with HTML 4 and XHTML1 documents published on the Web, but is not compatible with the more esoteric SGML features of HTML 4. HTML 5 does not have the same syntax rules as XHTML where we needed lower case tag names, quoting our attributes, an attribute had to have a value and to close all empty elements. HTML5 comes with a lot of flexibility and it supports the following features −
Uppercase tag names.
Quotes are optional for attributes.
Attribute values are optional.
Closing empty elements are optional.
The DOCTYPE DOCTYPEs in older versions of HTML were longer because the HTML language was SGML based and therefore required a reference to a DTD. HTML 5 authors would use simple syntax to specify DOCTYPE as follows −

The above syntax is case-insensitive. Character Encoding HTML 5 authors can use simple syntax to specify Character Encoding as follows −
< meta charset = "UTF-8">
The above syntax is case-insensitive. The < script> tag It's common practice to add a type attribute with a value of "text/javascript" to script elements as follows −
< script type = "text/javascript" src = "scriptfile.js">< /script>
HTML 5 removes extra information required and you can use simply following syntax −
< script src = "scriptfile.js">

HTML Style

Setting the style of an HTML element, can be done with the style attribute. The HTML style attribute has the following syntax:
< tagname style="property:value;">
The property is a CSS property. The value is a CSS value.