A List Apart: Test-Driven Progressive Enhancement
April 2020 note: Hi! Just a quick note to say that this post is pretty old, and might contain outdated advice or links. We're keeping it online, but recommend that you check newer posts to see if there's a better approach.
In issue 268 of A List Apart, our own Scott Jehl discusses our process of Test-Driven Progressive Enhancement. The article introduces a fresh approach to earlier research on the topic, and includes a full rewrite of the Javascript which is faster and more flexible for development. We will post details on the script API in the lab shortly.
Article link: Test-Driven Progressive Enhancement.