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2. History API
Pros
 Provides much-needed Back button support and
optionally deep-linking support for single-page apps
(SPAs)
Cons
 Provides limited freedom to modify backstack
IE Chrome Firefox Opera Safari
10+ 8+ 4+ 11.5+ 5+
http://www.whatwg.org/specs/web-apps/current-work/multipage/history.html

3. Geolocation API
Pros
 Simple, powerful, and easy to learn
 Works almost everywhere (including desktop browsers)
 Supports GPS, WiFi Positioning, and triangulation
Cons
 Provides no control over callback frequency
IE Chrome Firefox Opera Safari
9+ 5+- 3.5+ 10.6+ 5+
http://www.w3.org/TR/geolocation-API/

4. Audio and Video
Pros
 Provides native support for audio and video
 Eliminate need for Flash players, Silverlight players, etc.
Cons
 No standard audio or video file format
 No support for streaming, adaptive bitrates, or DRM
IE Chrome Firefox Opera Safari
9+ 4+ 3.5+ 10.5+ 4+
http://www.w3.org/TR/html5/the-video-element.html

5. Fullscreen API
Pros
 Provides full-screen support for all HTML
elements, including VIDEO elements
Cons
 Not supported in Internet Explorer
IE Chrome Firefox Opera Safari
- 15+ 10+ 12.1+ 5.1+
http://www.w3.org/TR/fullscreen/

6. Canvas
Pros
 Graphics API fills big hole in HTML
 API is rich (for 2D), yet relatively easy to learn
 requestAnimationFrame makes animations better
Cons
 API is primitive by today's standards
IE Chrome Firefox Opera Safari
9+ 4+ 2+ 9+ 3.1+
http://www.whatwg.org/specs/web-apps/current-work/multipage/the-canvas-element.html

7. Web Workers
Pros
 Allows for multithreaded JavaScript apps
 API eliminates most complexities from multithreading
Cons
 High overhead when transferring large objects between
threads (mitigated by new transferrable objects feature)
IE Chrome Firefox Opera Safari
10+ 4+ 3.5+ 10.6+ 4+
http://dev.w3.org/html5/workers/

8. Web Storage
Pros
 Allows Web apps to store data persistently on client
 API simple and easy to learn
Cons
 Data is stringified when stored and requires type coercion
 Recommended 5 MB storage limit is too restricting
IE Chrome Firefox Opera Safari
8+ 5+ 3.5+ 10.5+ 4+
http://www.w3.org/TR/webstorage/

9. Indexed DB
Pros
 Provides a structured alternative to Web storage
 Supports fast (indexed) retrieval from large data sets
 Supports transacted access and large storage volumes
Cons
 No query language; reads are case-sensitive
IE Chrome Firefox Opera Safari
10+ 11+ 4+ - -
http://www.w3.org/TR/IndexedDB/

10. Offline Apps
Pros
 Provides offline caching story for running apps when not
connected
Cons
 Story for updating cached content is confusing
 API could be richer
IE Chrome Firefox Opera Safari
10+ 5+ 3.6+ 12+ 4+
http://www.w3.org/TR/html5/offline.html

11. FileReader API
Pros
 Provides async API for reading files
 Relatively well-designed and widely adopted
Cons
 Reads were all or nothing until introduction of
slicing, which still isn't universally supported
IE Chrome Firefox Opera Safari
10+ 6+ 4+ 12+ -
http://www.w3.org/TR/FileAPI/

12. FileWriter and FileSystem APIs
Pros
 Provides much-needed API for file writing
Cons
 Specifications came very late, adoption has been slow
 Implementations to date only support virtual file systems
 API is complex and unintuitive (but fortunately async)
IE Chrome Firefox Opera Safari
- 13+ - - -
http://www.w3.org/TR/file-writer-api/ | http://www.w3.org/TR/file-system-api/

13. XMLHttpRequest Level 2
Pros
 Cross-origin calls via CORS protocol
 Support for progress reporting on file uploads
 Support for binary data transfers (send and receive)
 Support for request time-outs
 Cleaner, more consistent API
IE Chrome Firefox Opera Safari
10+ 7+ 4+ 12+ 5+
http://www.w3.org/TR/XMLHttpRequest/

14. WebSockets
Pros
 Push model for client-side updates
 Compatible with proxies and firewalls
 Supported in other platforms (e.g., Windows 8)
 Simple and intuitive API
IE Chrome Firefox Opera Safari
10+ 14+ 6+ 11+ 5+
http://dev.w3.org/html5/websockets/

15. Forms
Pros
 Allows for richer HTML UIs (finally!)
 Allows browsers to assume partial responsibility for
input validation (required fields, pattern fields, etc.)
Cons
 Should have happened a long time ago
 Not ambitious enough in scope
http://www.w3.org/TR/html5/forms.html