HTML is great for declaring static documents, but it falters when we try to use it for declaring dynamic views in web-applications. AngularJS lets you extend HTML vocabulary for your application. The resulting environment is extraordinarily expressive, readable, and quick to develop.
Other frameworks deal with HTML’s shortcomings by either abstracting away HTML, CSS, and/or JavaScript or by providing an imperative way for manipulating the DOM. Neither of these address the root problem that HTML was not designed for dynamic views.
AngularJS is a toolset for building the framework most suited to your application development. It is fully extensible and works well with other libraries. Every feature can be modified or replaced to suit your unique development workflow and feature needs.I definitely agree that HTML isn't an ideal tool for today's web, so I found this an interesting premise—though at first glance I wasn't really sure what it would look like to build a framework that doesn't "abstract away HTML, CSS and/or JavaScript".
It turns out what they do is take HTML by the horns and bend it to their will, adding attributes, basically extending it to be something more like the language it should be in this day and age. A lot of the focus seems to be on automatic data binding, much like what Knockout does.
I ran through their tutorial, and it's pretty impressive. I had no idea people were doing things like dependency injection in Javascript, within a browser. Or that such good, behavior-driven unit testing was possible in Javascript.
Basically, what you do is link to their script and put their attribute in your <html> tag. That sets Angular loose in your page, and once it works its magic you can do things like iterate over collections simply by adding a custom attribute to an <li> tag, or invoke some advanced, route-based templating and partial-page inclusion, and even interpolate expressions like {{"here is" + "my text"}} right into the page text. This is all stuff I'm used to doing with a server-side framework so it's familiar, but it's very compelling to see so much of it pushed to the client. That just makes sense when more and more of the application is happening in the browser.
The dependency injection comes into play in enabling mocks for testing (which runs in-browser, pretty cool) and injecting advanced data handlers that interact with the server (in their example, a RESTful component for effortless CRUD).
Good stuff. Chances are really high that I'll be using Angular for my app.
