My recollection was that Prototype.js got a big boost in popularity early on on the back of its inspiration from Ruby on Rails (in the sense that abusing protot

My recollection was that Prototype.js got a big boost in popularity early on on the back of its inspiration from Ruby on Rails (in the sense that abusing prototype pollution to make DOM elements have useful methods was novel and cool). Dojo and friends were comparatively obscure/niche until much later. I recall only reading about Dojo years later, during the whole Comet hype. My impression of the era was that visual pizzazz was all the rage, and Scriptaculous really delivered on that front (Flash was also huge back then). Whereas full blown web apps were relatively rare and a lot of library consumers just didn't see the point of things like modularization (despite the interest in "proper" engineering from library authors like Dean Edwards et al) And even then, once interest in thick clients grew, Ext.js had a lot more fanfare among the heavier frameworks than the Dojos and MooTools, due to its focus on enterprise.