Homepage: http://www.extjs.com

Ext is a javascript framework (by its own definition) that utilizes and extends other javascript libraries. It started out as a project extending the Yahoo-library, making components like Grid, Splitbar, Tabpanel available. It has also an extended animation library that enables animation sequencing and synchronization. The creation and modification of DOM elements is very well optimized with the Ext DOM Helper Utility. They have even benchmarked the performance comparing to libraries like Scriptaculous' Builder and Mochikit, in favor of Ext. This is a good thing regarding the recent issues with browser memory leaks that have been caused by "bad cleaning" of DOM modifications with javascript. Ext supports three base libraries at the moment, which are Yahoo's YUI, Prototype and Jquery. A copy of one of those libraries is needed in order to work with the Ext scripts. Ext has an online build system for making a detailed version for the specific needs of the developer. The user interface is very intuitive, with just checkbox clicking to add/remove needed features. The size of the code ranges from around 100k to the full 500k at the time of this writing. When the user has chosen the suitable parts for the build, the site generates the code for downloading and it is ready to be used right away. The licensing differs a bit from most of the javascript libraries. Ext has three levels of licensing options, one of them being the Open Source LGPL license, which would cover KP-Lab purposes quite well, I suppose.


- very good examples online
- good looking widgets (very objective here…)
- seems like they have studied the existing frameworks/libraries and done most of the things better
- time spent not only working with browser differences but actual optimization. E.g. the TreePanel works really well even with big amounts of data and nodes
- open source (at least in the scope of KP-Lab needs)


- size? Needs a base library to function and adds its own code on top of that. Might easily exceed what some might call quick, small and handy. Still, there is the build system for removing parts that are not needed, thus reducing the size.
- licensing – not totally open source, commercial options available too, depending on use, naturally

Web 2.0
Category AJAX frameworks

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This page (revision-1) last changed on 18:24 25-Mar-2017 by Samuli Toivonen.

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