"Frameworkless" doesn't necessarily imply going "full vanilla". It's possible to use libraries like µhtml (and related) to take care of some of the tedious details while having your own code supply the plumbing of the client side page/application.
Everyone needs a framework; what everyone doesn't need is a general purpose framework. Nobody has a general problem, everyone has a very specific problem they're trying to solve.
"Frameworkless" doesn't necessarily imply going "full vanilla". It's possible to use libraries like µhtml (and related) to take care of some of the tedious details while having your own code supply the plumbing of the client side page/application.
Rasmus Lerdorf - original creator of PHP
Nonetheless having knowledge of the more common Web APIs on a detailed level (first) is invaluable.