HTML5 in mobile devices

In mobile devices, HTML5 is often used for mobile websites and mobile applications on mobile operating systems such as Firefox OS, Sailfish OS, Tizen and Ubuntu Touch.

The AppCache, Indexed Database API, and Web storage makes it possible for mobile developers to store things locally on the device, so interruptions in connectivity will not affect the ability for someone to get their work done.

Offline support helps browsers cache static pages. They depend more on HTTP response headers sent by web servers to fetch HTML, CSS and multimedia required to render the web page. If everything required to render is cached, then a page loads quickly, but even if one item is not cached then everything slows down dramatically.

To provide offline support, a cache manifest file should be created to specify the offline application's resources—i.e. its pages, images, and other files needed to run offline. Typically, the manifest also contains a comment that is changed when any of the resources change, prompting the browser to refresh the cache.

The "manifest" attribute of the app's "html" element should specify the URL of the manifest file.

The proper MIME type "text/cache-manifest" should also be set on the server for the cache manifest. It should be noted that the use of "manifest" attribute is deprecated.

Sites can mark off a space on a page using a Canvas element where interactive pictures, charts and graphs, game components, and other imaginations can be drawn directly by programming code and user interaction — no Flash or other plug-ins are required.

Development is in the very early stages and subject to format disruption, but sites like YouTube and Pandora could one day skip Flash entirely and bring streaming audio and video, with timed playback and further features.

This is actually not part of HTML5, but is a separate specification. The geolocation API lets you share your location with trusted web sites. (This is actually the physical location of the device or of your internet connection, decided based on some combination of GPS, accelerometers, cellphone tower triangulation, and ISP address records.) The latitude and longitude are available to JavaScript on the page, which in turn can send it back to the remote web server and show you location-aware content like local businesses or show your location on a map.

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Wikipedia