HTML5 is simply the next revision of HTML.
HTML is the "content" of the app. CSS is the "styling" of the app.
The value of HTML5 is JUST needs HTML/CSS/JS using the web stack. You can use the web for the majority of applications out there. It doesn’t require multiple designers like it does on multiple platforms. HTML5 is just design for the "web"- native web components… it’s cheaper.
What about maintenance?
If you need to update your logo and your app is written in Java AND Objective-C AND a web app on Ruby. You have to touch/change/deploy each across three different codebases (not to mention distribution mechanisms – app stores).
HTML 5 doesn’t solve all problems, though it does reduce the headache. Maintenance becomes easier, it reduces dev and design costs. A single codebase can be used to do this.
Tools for the Web Stack
- Sencha Touch – Mobile JS framework for phones.
- Appcelerator Titanium – JS bridge allows you to develop for phones AND desktop
- jQuery Mobile – gracefully degrades very well for less capable phones.
- YQL – Yahoo Query Language, turns the entire web into an API. It helps you pull in lots of data (screenscrape) by Yahoo into XML.