While I find jQuery to be a delight to use, jQuery UI, is nowhere near what I would want/need it to be to build pure JS applications. The widgets it provides (accordion, datepicker, dialog, progressbar, slider and tabs) are not sufficient to define all of the UI in JavaScript in a clean way. No matter what you do you still have to define a lot of stuff using pure HTML.<p>Contrast this with ExtJS, where you can lay out the UI in pure JavaScript. Is anybody aware of anything like this built on top of jQuery?