很棒新特性：
图表 ：
Most people have used Ext JS 3’s Flash-based charting package. You’ll probably know that it’s good at the basics but is really hard to customize. For Ext JS 4.0 we’ve created a brand new charting package that is powered purely by JavaScript. We’ve united the phenomenal talents of Dmitry Baranovskiy (Raphaël JS ) and Nicolas Belmonte (InfoVis ) along with our very own Jamie Avins to create the most powerful JavaScript charting library we’ve ever seen.
大多数人使用的Ext JS 3图表是基于Flash图表包的，基本的图表它表现得很好，但是很难对它进行定制。对于Ext JS 4.0，我们已经创建了一个全新的图表包，它完全由JavaScript构建。我们将联合杰米Avins的德米特里Baranovskiy（拉斐尔波兰js）和尼古拉贝尔蒙特（InfoVis）的惊人才华创造最强大的JavaScript图表库。
The new charting package works on every browser we support (including IE6) and is fully integrated with the rest of the framework. We’ll be sharing a lot more detail about charting in the weeks to come; we’ve very excited about the new capabilities this offers all of our developers.
新的图表包工程将支持所有浏览器（包括IE6的），是完全符合框架的其他部分整合。我们将在未来数周分享有关图表来许多细节，我们一直非常关注这为我们开发的所有新功能感到兴奋。
主题 ：
Ext JS has always had a good looking theme, but with Ext JS 4 we’ve taken it to another level with a brand new theme called Neptune. This builds on the great looks and clean design of the current theme, but brings a whole new level of visual polish to your applications.
Ext JS一直有一个漂亮的主题，但在Ext JS 4我们将采用一个名为“海王星”的全新的主题。这种漂亮的外观和干净的设计，讲带为您的应用带来了一个全新的视觉效果。
But it’s not just a new theme – with Ext JS 4 we have used SASS from the ground up, making it extremely easy to customize your application’s theme any way you wish. SASS is already powering the Sencha Touch theme so check it out if you want to see just how easy this is going to be.
它不仅仅只是Ext JS 4一个新的主题，而是使用SASS方式构建，非常容易定制应用程序的主题。SASS已经在Sencha Touch中使用。
改进的数据包 ：
One of the strongest parts of Ext JS is the data package. This uses Stores, Readers, Proxies and the rest to seamlessly load data from any source and display it in your widgets. With Ext JS we’ve crafted a massively updated data package, with incredible new capabilities such as setting up relationships between Models and saving data to local storage.
Ext JS其中一个功能最强的地方是数据包。它通过Stores、Readers、Proxiex从任何来源无缝地加载数据并显示在在你的部件中。新版的Ext JS，我们将制作令人难以置信的新功能，一个大规模的更新数据包，如设立和模型之间的数据保存到本地存储的关系
Ext JS 4’s data package is shared with Sencha Touch so you can already use it in your apps today. We have several blog posts on the new innovations introduced in the new data package, all of which apply to Ext JS 4.
Ext JS 4的数据包包含在Sencha Touch中，因此你已经可以在你的应用中使用。我们已在几个博客中对对新的数据包中进行了介绍，这些讲适用雨Ext JS 4。
应用架构：
The first thing we ask ourselves when we get started writing an application is how to structure it. This leads to numerous problems – our time is taken away from the application itself, everyone comes up with a different architecture, and app architecture is just hard to do. With Ext JS 4 we’re addressing this long standing problem by shipping with a complete application architecture which can be used out of the box.
Ext js 4将采用统一的架构解决开发中结构松散的问题。
The application architecture is a standardized way of building applications. They all work the same way, follow the same patterns and have the same file structure. This enables us to create some incredible tools to help automate much of the design and maintenance that go into creating applications. It’s amazing how much easier it is to create applications using the new architecture, and you can even get a sneak peak by looking at Sencha Touch’s Twitter and Kiva examples.
We think this is the single most exciting part of Ext JS 4 and I know you’re going to love how fast and easy it makes application development. That said, we know some people have existing apps or their own approach to app architecture that they’d prefer to keep using so we’ve made it completely opt-in. We’ll have a lot more information on the application architecture before Ext JS 4 ships early next year.
升级的组件：
Every component in the framework has received attention for Ext JS 4. Firstly we’ve unified the rendering and layout of every component to make them all work the same way. We’ve been through component by component fixing bugs, improving UI and giving a new level of visual polish. Most components have become faster and more flexible than ever before.
Ext JS 4框架中的每个组件都将被重新构建。首先，我们统一了渲染和每一个部件的布局，使它们的工作方式相同。我们已经通过组件的组成部分修正错误，改进用户界面和给人一种新的视觉水平。大多数组件都变得更快，比以往更加灵活。
But we’ve also added new components to the framework. Two of the most popular extension components – RowEditor and TreeGrid – are now built into the framework itself, rewritten to meet the high quality standards we expect of Ext JS components.
我们也增加了新的组件。最流行的扩展组件RowEditor和TreeGrid将会被加入框架内。
取消FormLayout ：
When we asked what are the hardest things to do with Ext JS 3, one answer came up more than almost any other – laying out forms. Forms have always been tied to a FormLayout, which works like a straightjacket to limit a form’s flexibility. With Ext JS 4, forms can use any layout, making it easy to achieve any look and feel imaginable.
在Ext JS 3中最难的事情是什么？答案估计都一样：布局。而布局一直受FormLayout的束缚。在Ext JS 4中，可以使用任何形式的布局，因此很容易获得你需要的任何外观。
快速、易用和稳定
快速：
Everyone cares about performance – whether it’s how fast our applications load, how long they take to render and layout, or how fast they feel when interacted with. One of the most time-consuming parts of application execution is layout. Ext JS 4 features a brand new layout engine, using all of the experience we have gained crafting this framework over the last 4 years.
每个人都关心的性能 - 无论是我们的应用程序加载的速度有多快，多久，他们采取的渲染和布局，或者有多快，他们觉得当交互。对申请执行的最耗时的部分是布局。 Ext JS 4的特点是全新的布局引擎，利用我们掌握了过去4年这一框架方面的经验都各具特色。
Those who were able to join us at the conference saw just how fast the new layout engine is, and that it uses the exact same API as Ext JS 3. Although the layout engine is by no means the only performance improvement we have made, it has such a stunning impact that it deserves its own special treatment in a blog post nearer the release date. Ext JS 4 is far faster than anything we’ve ever created.
这些谁能够参加这次会议我们看到的是多么快的新布局引擎，而且它使用Ext JS 3完全相同的API。虽然布局引擎绝不是唯一的性能改进我们取得了，它有这样一个惊人的影响，是值得在临近发布之日博客文章自己的特殊待遇。 Ext JS 4是远远快于任何我们曾经创建的。
稳定：
For Ext JS 4 we have overhauled our quality assurance efforts to deliver the most stable framework we have ever conceived. To start with, the framework has the best test coverage it has ever enjoyed, with thousands of new unit tests ensuring that the code works properly.
对于Ext JS 4我们将努力为客户提供最稳定的框架内。首先，该框架具有最佳的测试覆盖，过去任何时候都享有与新单位确保正确的测试代码工作数以千计。
Unit tests are only part of the picture – we also need to ensure the visual components work properly. This has always been hard to do, so for version 4 we have invented a brand new tool that automatically exercises every component in the library. We drive this at the OS level, meaning we can test every OS/browser combination we support by simulating a user clicking around the interface. We call this incredible new tool Visual QA, and will be revealing more details about it soon.
单元测试只是其中的一部分 - 我们也需要确保可视组件工作正常。这一直是很难做到，所以对于版本4，我们发明了一种全新的工具，可自动演习中的每个库组件。我们开车在操作系统一级，这，这意味着我们可以测试所有的OS /浏览器的结合，我们通过模拟用户点击周围的接口支持。我们把这种令人难以置信的新工具Visual测试，并会透露更多关于它的细节很快。
易于学习：
Ext JS does amazing things, but has always been too hard to learn. With version 4 we’re rectifying this by creating the best documentation we have ever shipped. For a taste of things to come, check out some of the documentation in Sencha Touch. This is the standard we are striving for with Ext JS 4. We’ll also be creating guides, doubling the number of examples and providing sample applications.
Ext JS很好，但也很难学习。随着第4版，通过创建最好的文档，我们曾经解决学习难这个问题。类似于Sencha Touch的文档样式，将应用于Ext JS 4。我们也将创造指南，增加一倍的示范引导和提供的样本应用程序。
As well as documentation, the API has received a lot of attention with an effort to standardize on a published set of naming conventions and providing more sensible defaults for some of our configuration options. Lastly, we’ll be providing an upgrade guide and backwards-compatibility file to make upgrading to Ext JS 4 as painless as possible.
发布：
We’ve been working feverishly on Ext JS 4 for a long time, and are excited to be just a few weeks away from the first public beta. The framework is already more solid than it has ever been, so we can’t wait to get it into your hands. We expect to deliver a number of betas through the early part of next year, with a 4.0 final release currently planned for February 28th 2011.
I hope you’re as excited as we are about the incredible new features coming in Ext JS 4, and that you’ll continue to join us as we revolutionize the world of web application development.
计划于2011年2月28日推出。
原文出处：http://www.sencha.com/blog/2010/11/22/ext-js-4-preview-faster-easier-more-stable/