We're redesigning a website.  Right now it uses Dojo, a large (and complex) Javascript framework.   One person insists that we need Dojo because of things like (random examples)  client-side validation, cross-browser compatibility, and client-side data storage.After doing some checking, it seems like most of the things that Dojo provides are already built into HTML5.   In fact it seems like there's a lot of overlap:  Both provide client-side storage, client-side validation, and are at least partly supported by all major browsers.Would using HTML5 constructs eliminate the need for us to load this huge, complex and troublesome Javascript framework?   In general, does HTML5 take care of a lot of what Javascript frameworks were written for 10 or 15 years ago?
Does HTML 5 undercut the need for a full-featured Javascript framework?
javascript;html5
It depends quite a bit on the complexity of your application. But the general advantage in using a framework is that they generally target all major browsers, and are quite backward-compatible. Whereas if you rely on HTML5 only some features might only work with the latest browsers or not at all.I just tried <input type=datetime/> for example. Doesn't work in Firefox 34. But I am sure Dojo has a nice dropdown picker.Now, maybe Dojo is a bit too complex for your application. So you could check out jQuery and jQueryUI, which are a bit more lightweight.