Echo Web Framework

The fourth release candidate of Echo2 version 2.1 is now available. The most significant update in this release is that all JavaScript code in Echo2 and the Extras library has been migrated to use the CoreJS inheritance model. This modification slightly reduces the size of the JavaScript modules sent to the client browser, and offers a significant improvement in the readability of client-side code. The client-side APIs are unchanged by this move.

Hi all,

The "CoreDoc" tool has finally progressed far enough to generate useful API documentation for the JavaScript implementation of Echo3. This tool is capable of parsing Core.extend() blocks and properly marking static, virtual, and abstract methods. It additionally supports custom doc tags, which can be used to do things like specify the style properties and layout data properties that are supported by Echo components. The tool is not being written just to document the Echo API, but rather as a generic item for use with any project written using Core.js.

The first beta release of the Echo3 web application framework is available for download. Echo3 enables the development of AJAX-based web applications in either server-side Java or (new in Echo3) client-side JavaScript. Applications are developed using a component-oriented and event-driven API, similar to that of a desktop application user interface toolkit.

The server-side Java API of Echo3 that is used by application developers is based on that of Echo2. Application code can thus be easily ported from Echo2 to Echo3, often with not much more than a package-name change.

Hello all,

The big news in the past couple months of Echo3 development has been the maturing of the client-side version of the framework. This was accomplished largely by creating the Client-Side JavaScript Demo App, which currently stands just shy of about 5,000 lines of JavaScript code (note that line counts tend to be significantly lower for JS apps compared to server apps). The development of this application served three purposes: The first was nothing more than to show off what the framework can do and serve as a marketing tool. The second was to provide a proper example application. The third and arguably most important was to test and refine the client-side framework by writing a reasonably complex application with it.

The first Echo3 demonstration app is now online and available for download. This is an Echo3 version of the Echo2 "main" demo app, but with a twist: it was written entirely in the client-side JavaScript API of Echo3. It thus does not need an application server of any kind to operate. It can even be run from a local filesystem.

The application is available online here: http://demo.nextapp.com/echo3csjs, and may be downloaded with uncompressed source from the Echo3 download page: /site/echo3/download.

If you're new to the concept of JavaScript development with Echo3, be sure to check out the "JavaScript Development" demo screen. It offers a graphical demonstration of some of the more interesting features of the JavaScript side of Echo3, including Core.js-based inheritance and hierarchal component construction.

I finally took the plunge and picked up an iPhone a few days ago. While I was looking around for neat things that might be possible to do with it using Echo3, I ran into this page. It discusses the use of RFC 2397 (the "data" URL scheme) to embed images and even entire JavaScript/HTML applications into URLs. When you combine this with the fact that the iPhone now supports bookmarking web URLs and adding them to its "home screen", we have everything we need to create client-side Echo3 applications in JavaScript and package them up for offline iPhone use. That is, it's possible to create real Echo3 apps that can run even when the phone is out of network range or in "airplane mode".

There was one caveat: encoding URLs and applications using RFC 2397 is a horribly tedious process. My solution has been to throw together a proof-of-concept software development kit to take the pain out of it. You put in your JavaScript application and any other JS libraries you need, and out pops a ready-to-run offline Echo app for the iPhone. It can be downloaded from

Hi all,

As you may have noticed, the developer forums have now been fully integrated into the echo.nextapp.com web site. Please take note of the following:

Prior to January 23, 2008 at 00:30 UTC, the download link for 2.1.rc3 was in fact providing an older release. If you downloaded Echo2 2.1rc3 before this time, please re-download a new version immediately. While this problem did not affect all downloads, we highly recommend that you download a new version now to be certain you have the correct item.

You can verify that you have the correct version by one of two methods:

• Verify the file "/SourceCode/src/app/java/nextapp/echo2/app/ApplicationInstance.java" contains the text "2.1.rc3".
• In a browser, view the source of an Echo application compiled with your 2.1rc3 and be certain it contains the text "2.1.rc3".

A new, long-awaited release candidate of Echo2 is now available. This is mostly a bugfix release, bugs.nextapp.com is now nearly devoid of Echo2 bugs, please get them in soon if you want them fixed for 2.1 final. Downloads are available here: http://echo.nextapp.com/site/echo2/download

A new release of Extras is also available, version 0.9. Downloads are available here: http://echo.nextapp.com/site/echo2/addons/extras

A new EchoStudio build will be available soon, though there are a couple bugfixes in the queue before this one drops.