The usefulness of JavaScript libraries can be argued back and forward, but to insist that you are going to include a framework for every single project you have is absurd! If this trend continues, companies will have to filter out any web developers who insists that they have to include a 130Kb file to be downloaded by the client simply to utilize some client side scripting. Whatever happened to the people who doesn’t have high speed internet connections yet? And what of the people who are surfing on their favorite hand held devices?

As much as various JavaScript frameworks can help you finish things faster, I insist that any serious JavaScript developer should learn pure JavaScript from bottom up first, and not some PrototypeScript.