Yes, you really do need to learn JavaScript

From Ed Finkler’s PHP Advent 2009 piece, You Really Need to Learn JavaScript:

When I say “you need to learn JavaScript,” I don’t mean “learn how to copy and paste an example,” or “learn how to generate JavaScript with PHP.” I mean learn it as well as you already know PHP — or better.

Why? Because JavaScript drives rich clients, and all indications are that clients will be getting richer. You won’t be able to get away with just adding small snippets of JS to add tooltips and simple animations. Complex processing and UI management will require real knowledge of how to write JS, and how in [sic] interacts with the client’s APIs — the DOM, local storage, networking, OS features, and more.

And I will add: not jQuery, not MooTools, not Dojo, but real, actual, JavaScript (and DOMScripting). Finkler tells you why and points you to some resources for learning more.