AJAX frame works

it seems Jquery and Ext-JS are 2 main popular ones.
Jquery is light wight
Ext JS - graphical heavy and heavy weight components , it is good when you need all those graphical else lots of people are using Jquery , see these posts.

asr: see all that user responses to the post they all say they are happy with Jquery vs. Ext-JS
- dice.com Jquery serach has 300 jobs vs. 30 jobs for Ext-js/Ext Js


Why I didn’t switch from jQuery to ExtJS after all

Purpose

Most of what I use jQuery for is DOM manipulation, and occasionally a few effects. ExtJS is simply overkill. I do not need to use widgets for most clients or projects, so I do not. Instead, the lightweight jQuery lets me dart in, make a few DOM modifications, add a fade or two, and be done with it.

For example, the ExtJS grid is huge and powerful. I admire it. I just don’t need it. Nor do I want to wade through long tutorials to even begin to use it properly, even if I did have a need. In fact, I can’t think of a single client I’ve ever had who had a requirement which would have been a proper fit for that huge/powerful/gorgeous grid.
License

I do not wish to pay for my javascript framework, nor do I want to be forced to GPL it, as is the only other option available to me if I use ExtJS. I like the BSD license we use for Satchmo, and I am certain that we are not planning to change that any time soon.
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Why I should use jQuery?

Simple. In just one glance at the source code of a page using jQuery you’ll see how easy it is to use, how much it accomplishes in so few lines of code, and how graceful it is.

My mind was opened one day when I stumbled across some code written with jQuery. I was flipping through the RSS feeds and reading my daily dose of web design blogs when I came across an example of JavaScript loveliness that used jQuery. Truth be told, the code on that site had some browser related bugs… but the concept was something I hadn’t seen before.
What about the code?

The code looked almost simple. Like nothing I had seen before. It made sense.

I started reading through the documentation and was amazed to see how much could be done with so little extra code.
When you can use jQuery?

You should use jQuery when you need:

* A small library that gives you powerful control over the Document Object Model
* With very little effort or work on your part

Or

* Quick access to AJAX
* Without a lot of bloat (overhead - wasted code)
* And some basic animation effects to spice things up

But…

If you need super fancy effects for animation, drag and drop, and super smooth animation then you’ll probably want to use Prototype and one of the many great library created to enhance the effects.
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ExtJS Implementation Spotlight: Eaton’s Intelligent Power Manager

It Seems ExtJS Ext-js is good choice for graphical intensive systems , here is one big implementation of extjs


Did you evaluate other JavaScript frameworks for the Intelligent Power Manager? Why did you choose Ext?

We compared Ext JS to many popular libraries (jQuery, Prototype, MooTools, Script.aculo.us, Dojo, Rialto, Qooxdoo, etc.). We found Ext JS to be fully open source with a strong community combined with great technical support from the authors themselves. The Ext JS cross-browser widgets set is huge, which allowed us to complete our entire interface for Intelligent Power Manager.

asr: as this lead developer told , the above may be the JS frame works popularity order

Ext JS is a very well designed, lightweight framework which integrates core JavaScript language improvements, DOM manipulation helpers, and high level widgets – saving us several months worth of development.

Thank you for your article and all these great comments :) ExtJS is an awesome solution! By the way, Eaton Intelligent Power Manager is a team work done with Jérôme Lecuivre (project manager), Luc Descotils (software architect), Arnaud Quette (Open Source project leader http://www.networkupstools.org ), Sebastien Volle (Javascript expert), Eric Clappier (SNMP expert) and all Eaton test/validation teams. Moreover, if you have any questions or need any information, you can send me a mail to jonathanbonzy [at] eaton.com ;)