HTML5 is World Wide Web Consortium standard for the construction of web applications (including web applications for mobile devices) as opposed to the construction of classical websites.
In practice, HTML5 includes:
- Hypertext Markup Language (HTML, now in version 5)
- Cascading Style Sheet (CSS, now in version 3)
The relevance of HTML5 for mobile development is that the two major smartphone and tablet platforms, namely Apple’s IOS (used on iPhones and iPads) and Google Android, have HTML5 and CSS3 compliant browsers. In fact, both platforms use the same Webkit open source browser engine which means that, say, a web application which works correctly on an Android smartphone is bound to work correctly too on an iPhone.
- W3C Markup Validation Service (for HTML)
- W3C CSS Validation Service (for CSS)
The work to do is to progressively build a webpage such as the one shown above. You should use the latest HTML5 tags (such as header, nav, section, aside and footer) as well as CSS3 to style and format the content.