HTML5 Interview Preparation Guide

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HTML5 is being developed as the next major revision of HTML (HyperText Markup Language), the core markup language of the World Wide Web. The Web Hypertext Application Technology Working Group (WHATWG) started work on the specification in June 2004 under the name Web Applications 1.0. As of March 2010, the specification is in the Draft Standard state at the WHATWG, and in Working Draft state at the W3C.

► The canvas element: Canvas consists of a drawable region defined in HTML code with height and width attributes. JavaScript code may access the area through a full set of drawing functions similar to other common 2D APIs, thus allowing for dynamically generated graphics. Some anticipated uses of the canvas include building graphs, animations, games, and image composition.
► Timed media playback
► Offline storage database
► Document editing
► Drag-and-drop
► Cross-document messaging
► Browser history management
► MIME type and protocol handler registration

HTML5 is the proposed next standard for HTML 4.01, XHTML 1.0 and DOM Level 2 HTML. It aims to reduce the need for proprietary plug-in-based rich internet application (RIA) technologies such as Adobe Flash, Microsoft Silverlight, Apache Pivot, and Sun JavaFX.

► Cleaner markup
► Standardized approach to mobile devices support
► Additional semantics of new elements like <header>, <nav>, and <time>
► New form input types and attributes that will (and in Opera’s case, do) take the hassle out of scripting forms.

The new HTML5 specification allows browsers to prefetch some or all of a website assets such as HTML files, images, CSS, JavaScript, and so on, while the client is connected. It is not necessary for the user to have accessed this content previously, for fetching this content. In other words, application cache can prefetch pages that have not been visited at all and are thereby unavailable in the regular browser cache. Prefetching files can speed up the site’s performance, though you are of course using bandwidth to download those files initially.

HTML5 is the latest version of HTML standard supporting multimedia and graphical content.

HTML5 introduced many elements such as , instead of to support multimedia.

a) Cleaner markup
b) Additional semantics of new elements like <header>, <nav>, and <time>
c) New form input types and attributes that will (and in Opera’s case, do) take the hassle out of scripting forms.

We can display video using the tag as shown below:

<video width=“320″ height=“240″ controls=“controls”>
<source src=“test.mp4″ type=“video/mp4″ />
</video>

HTML5 offers two new objects for storing data on the client:

LocalStorage – stores data with no time limit

<script type=“text/javascript”>
localStorage.lastname=“ZAG”;
document.write(localStorage.lastname);
</script>

SessionStorage – stores data for one session.The data is deleted when the user closes the browser window.

<script type=“text/javascript”>
sessionStorage.lastname=“ZAG”;
document.write(sessionStorage.lastname);
</script>