The equivalent question several years ago was, "What was the easiest way to learn and write HTML?"
How do you display tables in a web page? Go to a page with tables, view-source and write the same. Alternatively, if its too tiring to surf the web for the feature you want to copy, just fire-up FrontPage or DreamWeaver (blasphemy!), create what you want (e.g. an image map) and view source. Tada!
Now, what's the easiest way to learn Ajax? e.g. the google suggest-ish auto-complete.
Simple as 1 2 3,
- Do it in Rails once: 3 steps demo (.mov file) or O'Reilly tutorial
- Re-implement the server-side yourself (this is the familiar part for most).
And of cos, arm yourself with some Ajax Debugging facility just in case.