Slashdot Mirror
Learning Ext JS
stoolpigeon writes "Rich Internet Applications (RIA) have often been associated with some type of sandbox or virtual machine environment to make desktop features available via the web. Many applications though, have left behind the restrictions and demands of those technologies, implementing RIAs as pure web interfaces. One key technology in this area is JavaScript. It's been well documented that working with JavaScript can be problematic across various browsers. In response a number of JavaScript libraries have been created to alleviate the issues in dealing with different browsers, allowing developers to focus on application logic rather than platform concerns. One such library, focused on providing tools for building RIAs is Ext JS. For the aspiring developer looking to use Ext JS, Packt provides a guide to the library in the form of Learning Ext JS." Read on for the rest of JR's review.
Learning Ext JS
author
Shea Frederick, Colin Ramsay, Steve 'Cutter' Blades
pages
309
publisher
Packt Publishing
rating
8/10
reviewer
JR Peck
ISBN
978-1-847195-14-2
summary
Build dynamic, desktop-style user interfaces for your data-driven web applications.
The book is written for people with experience in doing web development. The authors state that a working knowledge of HTML and CSS are important, but experience with JavaScript is not essential. I think that a reader that has not used JavaScript may want to supplement this guide with something that covers the basics of JS. Experienced developers that haven't worked specifically with web programming should have no trouble keeping up. Anyone completely new to the idea of programming, scripting, markup, etc. really will need to take some time to get familiar with those concepts before they dive into this book. The authors do not spend time teaching programming, they are focused purely on realistic applications of Ext JS.
The authors begin by stating that, "Ext is not just another JavaScript library..." and it is understandable that they would feel this way. I am unsure why one wouldn't think so other than a personal preference for the product. That said Ext JS can be used alongside other JS libraries and does provide a lot of features 'out of the box' that make it an attractive choice. The emphasis on RIA widgets and building strong applications is nice as Ext JS is not working to be all things to all developers.
The book is heavy on code and examples but not so much so that it falls into the cook-book style of writing. Learning Ext JS is more of an extended tutorial with ample explanation to help the reader not only understand the code but why certain choices are made. Frederick, Ramsay and Blades have done a good job of working through the examples in a concise manner. While the book is the result of group work, it does not have the feeling of being written by a community. I did not run into an abundance of repetition and topics flowed well. Learning Ext JS also covers installation and integration of the library as well as a very quick survey of tools for development. While short these sections would be extremely important to anyone coming into web development with little experience.
It's a quick read, and doesn't delve extremely deeply into more advanced topics. Rather, a reader new to Ext JS will get a launch that should make the library usable in a practical way and also give them the framework to push deeper. The book was written and published just as Ext JS moved between versions. The new version is backwards compatible with the material in this book and a number of the changes in version three would not have fallen within the scope of this book, so it is still a good place to get started with Ext JS. Those who want to dig deeper will need to look elsewhere.
The brevity of the book wont work for those folks who want to really dig down deep into Ext JS. I on the other hand, wasn't looking for a massive tome to lug around and grind through. I was happy to have a very accessible tool that would get me started quickly and that is what I got. On the other hand I do like to be able to find what I need quickly and nothing is more important to me when learning than a solid index. Unfortunately the only really large ding I have for the book is that the index is weak. It would be a lot worse if the book were larger, so the brevity helps here a bit, but it's still unfortunate. This does make the ebook version a little more attractive. Packt will bundle them at a cost that makes the addition of the electronic copy very attractive. That said, the easy flow does it make it easy to read this book front to back while working the examples. Learning Ext JS just wont be my first choice when I need to quickly check a reference.
I've discussed the shallow coverage, but this does not mean that the book is not useful. The Ext JS library bundles enough functionality into the stock widgets, that decent applications could be written with nothing more. Creating custom widgets is covered and extending existing code as well, but this is later in the book. The material prior to that covers not only the use of the provided widgets but how to tie them together, theme an app and then handling data. This means the reader pretty much has everything in hand to build a stock application. The focus is on dealing with these issues on the client side. The examples do include a small amount of back end code when necessary for the execution of examples. All the examples are available to download from the Packt site and come packaged with all necessary scripts, images, etc.
I've always worked primarily with desktop applications. I've done some work with web applications, but it seems to me that increasingly the tools that I use the most are web based. With technology like Google Gears making those applications available whether I'm connected or not they have become much more attractive. Tools like Ext JS make it much easier for me to transition over to this new way of developing applications. I've found that Learning Ext JS has been a valuable resource in taking what is a great resource and allowing me to get the most out of it more rapidly than I would have otherwise.
You can purchase Learning Ext JS from amazon.com . Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page.
The authors begin by stating that, "Ext is not just another JavaScript library..." and it is understandable that they would feel this way. I am unsure why one wouldn't think so other than a personal preference for the product. That said Ext JS can be used alongside other JS libraries and does provide a lot of features 'out of the box' that make it an attractive choice. The emphasis on RIA widgets and building strong applications is nice as Ext JS is not working to be all things to all developers.
The book is heavy on code and examples but not so much so that it falls into the cook-book style of writing. Learning Ext JS is more of an extended tutorial with ample explanation to help the reader not only understand the code but why certain choices are made. Frederick, Ramsay and Blades have done a good job of working through the examples in a concise manner. While the book is the result of group work, it does not have the feeling of being written by a community. I did not run into an abundance of repetition and topics flowed well. Learning Ext JS also covers installation and integration of the library as well as a very quick survey of tools for development. While short these sections would be extremely important to anyone coming into web development with little experience.
It's a quick read, and doesn't delve extremely deeply into more advanced topics. Rather, a reader new to Ext JS will get a launch that should make the library usable in a practical way and also give them the framework to push deeper. The book was written and published just as Ext JS moved between versions. The new version is backwards compatible with the material in this book and a number of the changes in version three would not have fallen within the scope of this book, so it is still a good place to get started with Ext JS. Those who want to dig deeper will need to look elsewhere.
The brevity of the book wont work for those folks who want to really dig down deep into Ext JS. I on the other hand, wasn't looking for a massive tome to lug around and grind through. I was happy to have a very accessible tool that would get me started quickly and that is what I got. On the other hand I do like to be able to find what I need quickly and nothing is more important to me when learning than a solid index. Unfortunately the only really large ding I have for the book is that the index is weak. It would be a lot worse if the book were larger, so the brevity helps here a bit, but it's still unfortunate. This does make the ebook version a little more attractive. Packt will bundle them at a cost that makes the addition of the electronic copy very attractive. That said, the easy flow does it make it easy to read this book front to back while working the examples. Learning Ext JS just wont be my first choice when I need to quickly check a reference.
I've discussed the shallow coverage, but this does not mean that the book is not useful. The Ext JS library bundles enough functionality into the stock widgets, that decent applications could be written with nothing more. Creating custom widgets is covered and extending existing code as well, but this is later in the book. The material prior to that covers not only the use of the provided widgets but how to tie them together, theme an app and then handling data. This means the reader pretty much has everything in hand to build a stock application. The focus is on dealing with these issues on the client side. The examples do include a small amount of back end code when necessary for the execution of examples. All the examples are available to download from the Packt site and come packaged with all necessary scripts, images, etc.
I've always worked primarily with desktop applications. I've done some work with web applications, but it seems to me that increasingly the tools that I use the most are web based. With technology like Google Gears making those applications available whether I'm connected or not they have become much more attractive. Tools like Ext JS make it much easier for me to transition over to this new way of developing applications. I've found that Learning Ext JS has been a valuable resource in taking what is a great resource and allowing me to get the most out of it more rapidly than I would have otherwise.
You can purchase Learning Ext JS from amazon.com . Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page.
Can you give an example of such a "proper" website? Something with a .gov extension perhaps?
I was working on a large scale project (with way too much application-like behavior on a web page) that switched from DOJO to EXTJS. We were planning on using their LGPL version at the time. EXTJS actually turned out to be one of the better toolkits out there as far as documentation and clarity in the API went and things were looking pretty good. Then, one day the people behind EXTJS announced a licensing change. This would have been fine under normal conditions, but they claimed that it never was released under the LGPL. They tried some silly technicality where they said it was only released under the LGPL under some other terms. The LGPL itself clearly says any added terms can be removed, but they insisted it couldn't. We had a big enough corporate backing where buying licenses was an option, and was pretty likely as things got closer to deploying, but this really shook us up. These guys totally screwed over a large part of their community. I strongly believe they are wrong about the "never being under LGPL" thing, but we weren't going to be wasting time dealing with lawyers and fighting them. It was a lot easier to drop ExtJS from our project and go switch to another toolkit (eventually YUI). So, anyway, just a disclaimer the company behind EXTJS is EXTREMELY unprofessional, and bad to deal with. They now claim to have a GPL version, but that is only useful if you plan on keeping your code open. A lot of people may think, it's web client code, who cares, but for some of us web client code is becoming more and more like any other application code. So, the moral of the story is, ExtJS is a nice toolkit, but the corporate entity behind it is terrible and will stab you in the eye. Avoid using them at all costs!
I've been doing a lot of work with extjs for building web applications (business type apps with Domino or Salesforce as the back-end source), and for that its great. From time to time I've looked at using parts of it for web pages and it fails for a couple reasons.
The big one is that you want to design things from the outside in, with containers in containers and layouts within layouts. Which is perfect for totally controlling the behavior of an entire page to make it look at feel like an application. However, if you just want to put a menu on a page, the container hierarchy becomes cumbersome.
Course, this is all just my opinion. Can't prove any of it.
"Have you ever thought about just turning off the TV, sitting down with your kids, and hitting them?"
One of the editors of the RIA wikipedia page keeps reverting any changes made which make reference to the fact that, overwhelming evidence to the contrary, extensive use of javascript does actually qualify as creating applications that are "Rich".
it would be very helpful if someone (other than myself) could review the discussion, add references to this book, citing it as an example of how javascript can, if utilised correctly, result in "Rich Media Applications".
Too many JS toolkits!
Will it ever settle down?
You can't know and test for all known web browsers, nor can you test in future browsers that don't exist yet.
That's correct, but I can update the Javascript framework I'm using, which does get updated as browsers are released.
Did you know that JavaScript has feature sniffing that is a perfectly viable alternative?
Of course, as soon as Ext starts using feature checking then my applications will too. Until then, I'll continue writing one piece of code that runs the same in all browsers.
"Our two-party system is like a bowl of shit looking at itself in a mirror." - Lewis Black