Learn web/browser API's
The BOM and the DOM are not the only browser API's that are made available on the web platform inside of browsers. Everything that is not specifically the DOM or BOM, but an interface for programming the browser could be considered a web or browser API (tragically in the past some of these API's have been called HTML5 api's which confuses their own specifics/standardize with the actual HTML5 specification specify the HTML5 markup language). Note that web or browser API's do include device API's (e.g. Navigator.getBattery()) that are available through the browser on tablet and phones devices.
image source: http://www.evolutionoftheweb.com/
You should be aware of and learn, where appropriate, web/browser API's. A good tool to use to familiarize oneself with all of these API's would be to investigate the HTML5test.com results for the 5 most current browsers.
Learn:
- DIVE INTO HTML5 [read]
- Pro HTML5 Programming [read]
Learn Audio:
- HTML5 Canvas [read]
- Fun With Web Audio [watch]
- Add Sound to Your Site With Web Audio [watch]
Learn Canvas:
- Web Audio API [read]
Additionally, MDN has a great deal of information about web/browser APIs.
- MDN Web API reference
- MDN WebAPI - lists device access APIs and other APIs useful for applications.
- MDN Web APIs interface reference - all interfaces, arranged alphabetically.
Keep in mind that not every API is specified by the W3C or WHATWG.
In addition to MDN, you might find the following resources helpful: