One of my resolutions this year was to contribute to the AJAX Control Toolkit for the ASP.NET AJAX Framework. I began my AJAX Control Toolkit development quest by digging into the online resources, reading ASP.NET AJAX in Action, and decomposing the AJAX Control Toolkit. I noted the huge learning curve required to developing a control, and continued to dig deeper. Once mired in ASP.NET AJAX a bad smell kept wafting by. Since then I've been trying to distinguish this smell.

What's really wrong with ASP.NET AJAX? What's that bad smell?

• It doesn't plan for performance from day one
• It treats AJAX as a classic computer science problem
• It tries to turn JavaScript into a classical language which works against JavaScript's dynamic, prototypical nature
  

A Case Study: Why Plaxo.com Almost Failed

In the video: High-performance JavaScript: Why Everything You've Been Taught is Wrong (YUI Theater) Joseph Smarr discusses the challenges and lessons learned while developing Plaxo.com. While developing this AJAX centric application, the Plaxo team decided to include everything they could think of (including the kitchen sink) into their application. They created a framework to treat JavaScript as a classical language, they gave priority to features over performance, and... the project ALMOST FAILED. They were able to salvage their application by diverting their development efforts, making performance one of their top priorities, by unlearning everything they'd been taught about classical applications (instead embracing JavaScript), jettisoning unneeded framework bloat, and more.

Some of the points made in this video were:

• Plan for performance from day one
• AJAX is not a classic problem
• JavaScript is not a classical programming language
• User experience and a responsive application can make or break an application
• Unneeded bloat in a framework, and an obtuse approach to using AJAX (treating AJAX and JavaScript as a classical language or classic computer science problem) has the potential to cripple your application

This Channel 9 video also mirrors these sentiments: Douglas Crockford, Alex Russell and Joseph Smarr: On the Past, Present and Future of JavaScript

How ASP.NET AJAX Failed: What can we learn from Plaxo?

The way the Plaxo team approached their application development is similar to how the ASP.NET AJAX Framework has been designed. Like Plaxo's initial attempt ASP.NET AJAX attempts to mold JavaScript into a classical language, and attempts to treat JavaScript and AJAX as a classic computer science problem by heaping on more abstractions. Like Plaxo's initial attempt ASP.NET AJAX also gives a low priority to performance. Plaxo was able to change their direction and salvaged their application, but the ASP.NET AJAX Framework is not in a position to make any sweeping changes - ASP.NET AJAX is going down the wrong path and it's too late.

The ASP.NET AJAX Framework is probably another exercise in Framework Architecture (Demoware) and a failure in practice. Its lack of use in the wild attests to these shortcomings - contrast the sites using ASP.NET AJAX with the sites using jQuery (Actions Speak Louder Than Words). Furthermore the places that ASP.NET AJAX does thrive (the small internal ASP.NET business apps that need some bling-bling) will also be the areas that Silverlight shines - Silverlight offers a better Microsoft centric programming model (less leaky Win Form / Web Form abstractions) that most Microsoft developers will embrace. Silverlight will probably divert the developers that currently embrace ASP.NET AJAX.

I don't recommend the ASP.NET AJAX Framework and won't be contributing to the AJAX Control Toolkit. My time is better spent elsewhere.

There's no need to whip a dead horse (I've probably been griping about the ASP.NET AJAX Framework for too long), but... Jon Galloway and a group of other notable gurus (K. Scott Allen, Scott Koon, and Kevin Dente) have started a podcast, their latest segment sparked my interest since it covered ASP.NET AJAX and AJAX Libraries / Frameworks in general.

I share their sentiments so I thought I'd post a brief but choppy transcript:

[ASP.NET AJAX] ... does offer some some nice features, they did try to take some of the common pieces of the CLR that [.NET Developers are] used to working with and move that down into a JavaScript library. So you get classes like a WebRequest class that wraps the XMLHttpRequest ... and they have a StringBuilder, and they added methods that we're more accustom with ...

that's wonderful, but I don't find myself needing those extensions all that often. If you want to do strictly client-side programming then something like jQuery offers you a lot more capabilities to do things that you really want to do client-side like sorting and CSS selectors. ... That stuff is easy to do with an Update Panel and ASP.NET, but Update Panels aren't always the best solution to use. ...

the goals with ASP.NET AJAX was to integrate into the ASP.NET server-side model ... that's great for ASP.NET, but it needs more client-side features. ... It works if your thinking from the ASP.NET control perspective, but if you look at it outside the ASP.NET model there are a lot easier ways to do it. ...

ASP.NET AJAX [development] seems to have come to a standstill I'm not seeing a lot of development in that area and the rest of these [AJAX] Frameworks are doing monthly releases. Every month that goes by [the ASP.NET AJAX Framework] falls further and further behind ... it needs to evolve.

Listen to this great podcast here: Technology Round Table Podcast #2 - AJAX Frameworks

Douglas Crockford opens his latest book with these words:

Most programming languages contain good parts and bad parts. ... [the language designers or architects] are usually powerless to do anything except heap more features on top of the existing pile of imperfections. And the new features do not always interact harmoniously, thus producing more bad parts. - JavaScript: The Good Parts by Douglas Crockford

His words can apply to all programming languages and frameworks. Especially the ASP.NET Framework and Visual Studio.

Bad parts in the ASP.NET Framework and Visual Studio:

• ASP.NET Themes and Skins
• The ASP.NET AJAX Framework
• ASP.NET / Visual Studio Inline Style Properties
• Visual Studio Design View
• ASP.NET and Visual Studio's over dependency on XML configuration files
  

It would be great if someone wrote a book outlining the good parts of ASP.NET and Visual Studio. :)

What bad parts do you steer clear of?

Back when the web turned 2.0, AJAX was all the rage, and gas was cheap, a Google recruiter contacted me. We worked through a couple screening interviews - I explained how I was a .NET / ASP.NET / C# developer with some experience with Java and PHP, I described how C# was somewhat similar to Java. Things went great, I moved on to the next step of the process - writing code (a JavaScript widget for Gmail) with a 2 day (weekend) hard deadline. At the time I was wearing JavaScript diapers, but tried the exercise anyways - I'm still convinced the recruiter confused my Java / C# experience with JavaScript. Anyhow...

The Google Web Developer Exercise:

Web Developer Exercise

Attached are three states of a new contacts widget. This widget will be used across Google and may be anywhere on the page. Designers will also use this in mocks for usability tests. Create the HTML, CSS, and JavaScript for the widget as described in the image. Your solution must work in Firefox v1.5+ and IE v6+. Bonus points for a solution that degrades nicely on older browsers.

After my first attempt, I concluded that:

1. My JavaScript knowledge was embarrassing
2. Dynamic programming languages like JavaScript using prototypical inheritance were awesome - as a monocultured .NET developer I had sorely been missing out
3. Framework Web Developers (ASP.NET, Ruby on Rails, and so on) aren't really Web Developers - we depend on a framework (an API) as a crutch, where the law of Leaky Abstractions is very real, and often when it rears it's head we use our golden hammer (our multipurpose language of choice), but there are better tools at hand
   
4. Web Developers claiming n years of experience need to at least know JavaScript, CSS, HTML / XHTML, a server-side language, and some XML / XSL - NOT just a single multipurpose language or framework
   
5. Innovation can only happen when you become one with the technologies surrounding your realm - for example: Jesse James Garrett probably would not have publicized AJAX had he been an exclusive ASP.NET developer, David Heinemeier Hansson would have never created Rails had he been an exclusive ASP.NET developer, and Scott Guthrie would never have developed ASP.NET had he been an exclusive ASP.NET developer. Diversity is essential for innovation
   

In retrospect this exercise is brilliant, it's a more complex derivation of a Fizzbuzz exercise, which effectively weeds out the knowledgeable candidates from the n00bs. JavaScript is notorious for being one of the world's most misunderstood language, many developer (and the ASP.NET Framework) still use JavaScript techniques from the old days of Netscape. For example: <a onclick="return false;" ..., or <a href="Javascript: do something;" ... are common DOM Level 0 inline techniques that should be avoided. These techniques have been replaced, but finding developer that use these JavaScript techniques can be hard.

By having a developer complete this exercise you effectively determine that the they understands these concepts:

• Cross browser compatibilities and work arounds for both JavaScript and CSS - with a preference given to feature detection (object detection) vs browser detection, an understanding of the different event handling models between browsers
  
• An understanding of the separation of concerns - JavaScript, markup, and CSS should be separate files, or at least separated within the document
  
• Event registration and listening - DOM events, the different browser event models, no inline level 0 event declarations, no pseudo JavaScript protocol inline declarations within markup
  
• An understanding of functional languages - closures, namespaces, lambdas, recursion where necessary
  
• Node manipulation - creating, swapping, removing elements
• Knowledge of non-obtrusive JavaScript techniques
• Importance of modular / compartmentalization of CSS and JavaScript - defensive programming techniques that minimize the risk of interfering with other scripts and elements within the page, part of the non-obtrusive techniques, how to avoid global variables
• An understanding on how to debug JavaScript from both IE (link) and Firefox (link)
• JavaScript code conventions - naming conventions, statement conventions
• CSS naming conventions
• General DHTML / AJAX techniques - showing and hiding elements
  
• A gauge on their attention to details and UI design intuition - what their gut tells them to do when things aren't spelled out

My latest crack at the Google Web Developer Exercise:

You'll have to visit my site (view this blog post outside a RSS reader) to view the code in action.

The code: GoogleExercise.js, GoogleExercise.html, GoogleExercise.css

Today I'm wearing JavaScript training wheels - feel free to comment on the code, I'm always looking for improvements and suggestions. I did take a couple shortcuts on the CSS / UI side of things as I was focusing more on the functionality.

Using one of the AJAX Libraries (like jQuery) we could certainly do this exercise in significantly fewer lines of code.

An anticlimactic conclusion about the ASP.NET AJAX Framework - this framework's niche seems to be the internal (intranet) business application realm that depend on ASP.NET Web-Forms. These applications have a handful of users, a couple developers, no performance or bandwidth requirements, little ambition for future growth, and the developers typically embrace dragging & dropping controls in Visual Studio. In this case the ASP.NET AJAX Framework provides some eye candy, and patches the broken Web-Form metaphor by cramming AJAX into the ASP.NET model, but then comes along the ASP.NET MVC Framework, Silverlight, WPF and ... ??? Goodbye ASP.NET AJAX!

Interesting observations:

How many applications explicitly state that they use the ASP.NET AJAX Framework?

• 25, this includes sites like DotNetNuke (with a reputation of being slow), view the list here.

How many of these applications are relatively high-traffic?

• None. ZERO!

How many applications explicitly state that they use the YUI AJAX Library?

• 89, view the list here and here.
  

How many of these applications are relatively high-traffic?

• Quite a few. A couple notable sites: Flickr, Slashdot, Linkedin, Paypal, O'Reilly, My Opera.

How many applications explicitly state that they use the jQuery AJAX Library?

• 516, view the list here.
  

How many of these applications are relatively high-traffic?

• Many. A couple notable sites: Twitter, Digg, Dell, Slashdot, BBC, Netflix, Technorati, New York Post.

If no high-traffic application uses the ASP.NET AJAX Framework then why would you? Actions (or lack of action) often speak louder than words, and it appears that the ASP.NET AJAX Framework is not suitable for the real world.

Forums or Newsgroups are a great way to expand your community, contribute to the greater development community, hone your communication skills, and stay grounded. However, forums can have a frustrating dark side. From what I can tell, the dark side of forums stem from the wide diversity of users.

On Forums we have:

• the normal users
  
• the newbies
• the trolls
• the users suffering from information fatigue syndrome
• in some cases full time employees

As a forum contributor, I like to think that I'm giving something to the community, but some days I feel like I'm wasting my time and here's why.

Frustrating forum threads:

When contributors pass your words off as their own:

Amanda from Microsoft offers this bit of advice on 08-28-2007:


Which seems vaguely similar to something I might have said back on 12-07-2006:

When users are belligerent:

"Adam has so little time he can't even read your question ..." - Brian

When users want a quick fix or want you to do their work:

"please verify and do for me some work." - dagamishiva

It makes it all worth while when users are genuinely grateful for your advice and suggestions. In the end, forums (and helping people in general) is rewarding, and some forums that explicitly cover more advanced topics omit the frustrating chatter and facilitate professional level discussions.

What are your experiences with forums?

The ASP.NET AJAX Framework is an embarrassing server-side centric approach to DHTML / AJAX web development. While most programming languages and frameworks come with both good and bad parts, the ASP.NET AJAX Framework is probably an example of an overall bad part of ASP.NET - on the contrast the ASP.NET MVC Framework looks to be a good part.


What's wrong with the ASP.NET AJAX Framework?

1 .NET Developers are DUMMIES!
The ASP.NET AJAX Framework appears to have been designed under the assumption that .NET developers are dummies and can't learn or don't want to learn JavaScript. That .NET Developers would rather hobble along with their familiar languages, then to learn something new. I understand that the ASP.NET community's only real problem is education, so let's ask: What is wrong with the ASP.NET Community? Then educate ourselves rather than becoming the .NET Developer statuesque. It's patronizing to use a framework that assumes learning a new language is beyond our capabilities. Many of these other programming languages also happen to be more expressive than the statically typed .NET languages.

2. The "don't write a line of JavaScript" abstraction leaks like a sieve
The Framework is intended to shelter .NET Developers from the big bad JavaScript language. Which, like driving a car across North America without knowing how to pump gas, stops you dead. Either you depend on someone to pump your gas - depend on something like the ASP.NET AJAX Control Toolkit and the many authors to write your JavaScript - or you stop moving. As Web Developers, sooner or later learning how to pump your own JavaScript becomes a mandatory skill.

3. Client-side programming from the Server-side is a absurd
The AJAX Framework does back flips to translate server-side code into JavaScript, and then requires that you write JavaScript anyway. Save yourself the pain, learn JavaScript. One day The Law of Leaky Abstractions comes into play, the gas station attendant fills your gas tank with diesel - your AJAX Control Toolkit blows up (requires debugging) so you have to learn JavaScript anyways.

4. Bloated, poor performance, bad user and developer experience
The AJAX Framework extends many of the native JavaScript objects as it attempts to turn JavaScript into a staticly typed programming language, and tries to hook into the ASP.NET life cycle, but all these features are unneeded as they are ALL already achievable through the native JavaScript language - if it walks like a duck and quacks like a duck, then... err... could someone remind me why we need typed languages in a web browser? Anyhow; all these object extensions, enhancements, and upgrades, contribute to more scripts that need to be downloaded and increases the number of scripts running in your browser. Then to make matters worse there's partial-page rendering and Update Panels which do full page post backs under the guise of AJAX -bad-bad! Client-side scripting is supposed to enhance the user experience not make it worse. Other AJAX Frameworks are built with performance as their number one goal, but in the ASP.NET AJAX Framework. Adding more widgets to JavaScript seemed to be the first priority, and performance an after thought.

5. Working against the grain is a waste of time
The AJAX Framework works against the grain, it would be nice if it embraced the JavaScript language. Very few of the concepts and metaphors used in the ASP.NET AJAX Framework transcend AJAX techniques or frameworks - your time is probably better spent learning how JavaScript works or how the other AJAX frameworks work.

6. Disconnected from the ASP.NET MVC Framework
The ASP.NET MVC Framework throws the ASP.NET life cycle away leaving more dead weight ASP.NET AJAX Framework script and rendering many of the AJAX Framework techniques moot.

7. The ASP.NET AJAX Framework almost over looks the 'J' in AJAX - 'J' stands for JavaScript, and that is GOOD
JavaScript is the glue of the web, even the ASP.NET Framework depends heavily on JavaScript, it is not something to shy away from.

8. Aside from local intranet sites, no one really uses the ASP.NET AJAX Framework.
The AJAX Framework isn't widely used. The ASP.NET AJAX site showcases 25 sites using ASP.NET AJAX. None of these applications appear to be high-traffic or moderately high-traffic applications. On the other hand, the YUI site showcases 89 sites, out of these sites, 6 sites (flickr, Slashdot, Linkedin, Paypal, O'Reilly, My Opera) could be considered high-traffic. Other AJAX libraries like jQuery, and Dojo compare similarly. Your time might be better spent learning one of the other AJAX frameworks.

If we (.NET Developers) are going to claim we know AJAX, then let's focus on the core of AJAX (JavaScript) and stop obscuring it in poor frameworks. Frankly the ASP.NET AJAX Framework is embarrassing, the web development community is laughing at the ASP.NET AJAX Framework and the Developers touting it.

The authors of ASP.NET AJAX in Action did an OK (Average) job at presenting the ASP.NET AJAX Framework. However; this book lacked objectivity and suffered from hype. The authors didn't seem to have proficient experience with the JavaScript language, or enough experience with other AJAX Frameworks / Libraries, or sufficient experience using the ASP.NET AJAX Framework in real world projects. This book sadly felt like most technical books - average.

Comments like "we recommend that...", "because it makes no sense...", "you must rely on a special method...", "you must understand X,Y,Z to run complex client-side code without writing a single line of JavaScript" were discouraging. Many of the "whys" were left answered and the technical inner workings of the framework often trivialized. Don't get me wrong, writing a book is incredibly time consuming, but if you're an author, presenter or the like, and you don't fully understand something then admit it. Do some research, provide some links, or move on. Consistently making comments like these bring the integrity of the whole text into question.

The ASP.NET AJAX Framework itself is technically flawed, bloated, and almost entirely impractical. I was disappointed with the server-centric approach that both the book and ASP.NET AJAX Framework takes. I was disappointed that the book continually pushed JavaScript under the carpet as magic and at the end of the book I was pleased to see the promise of making "the JavaScript code disappear" never was  fulfilled. JavaScript is the very most important part of AJAX, without the 'J' in AJAX, we're left with nothing - just 'Asynchronous', 'And', heaps of more ugly 'XML'.

When reading this book, take the contents and the ASP.NET AJAX Framework with a grain of salt, if you're really serious about learning AJAX then read JavaScript: The Definitive Guide by David Flanagan.

I typically only contribute positive reviews, but I don't agree with the majority of reviews found on Amazon and hope this review provides some objectivity. I commend the authors on their hard work, I'm probably being too harsh with this review - I know it's tough to write a book, and imagine they made many sacrifices as they worked towards tight deadlines.

View my review on Amazon.

The ASP.NET AJAX framework comes with a lot of baggage err... I mean... a huge learning curve when compared to other AJAX Frameworks like JQuery, YUI, Dojo, Prototype / Scriptaculous.

Here's a running list of the technologies, and concepts you'll encounter when digging into ASP.NET AJAX:

• ASP.NET
• The Page Life Cycle
• The Control Life Cycle
• Web Controls
• User Controls
• View State
• Session State
• Events
  
• .NET / Classical Language
  
• Interfaces
• Inheritance
• Delegates
• Multicast Delegates
• Assemblies
• Properties (Get / Set)
• Constructors

In addition to these, you also have the technologies universal to all JavaScript libraries:

• JavaScript:
• Closures
• Object Literals
• JSON
• Events
• DOM Manipulation
• Prototypical Inheritance
• Constructors
• XMLHttpRequest
  
• Cascading Style Sheets (CSS):
• Web Services

The ASP.NET AJAX Framework is more complex than other AJAX frameworks, I'm continually lost in it's ambiguity as it attempts to skirt around the JavaScript language - I think this learning curve (and all it's confusion) is precisely why Silverlight has so much potential.

I'm still diving into the low-level details, but my first impressions of the ASP.NET AJAX Framework are:

• Obscure, ambiguous, no clear vision - it offers multiple (resource intensive) ways to avoid writing JavaScript, but then requires that you write JavaScript anyways
  
• Too server centric
• Too heavy weight (I'm not appreciating how they're trying to turning JavaScript into a Java, C#, .NET clone, the overhead within the browser for these conversions seems like a huge performance bottleneck)
• Has the potential for poor performance

Most of the other AJAX libraries have been written with performance, browser responsiveness, and User Experience as their number one priorities - I'm still not sure about ASP.NET AJAX.

How many ways can we try to avoid writing JavaScript? If an AJAX library doesn't enhance the User Experience then why use it? Regardless, I'm still digging deeper.

A couple years ago I was thrown into a web application that made heavy use of ASP.NET Themes and Skins. Prior to this I depended exclusively on Cascading Style Sheet (CSS) for my web development / web design needs. A first glance at ASP.NET Themes and Skins looked promising, but a number of flaws surfaced - see the links and issues listed at the end of this post.

In addition to these issues, here are a couple other considerations when thinking about ASP.NET Themes:

• Themes do not adequately separate the levels of concerns within your application. When using Themes all design related files are baked into the application. From a maintainability standpoint, this doesn't bode well in large web applications. Hosting design related files on a single server or an external Content Delivery Network (CDN) is an effective way for managing site wide UI updates and increasing a sites performance, ASP.NET Themes works against this technique.
• Themes add unneeded complexity by obscuring the real technologies at work (CSS). Everything that ASP.NET Themes offer can be better achieved outside of the ASP.NET Theme Framework. Technologies like Cascading Style Sheets (CSS),  alternate Style Sheets, and JavaScript can achieve more than Themes can provide.
• Themes are a server-side mechanism. Themes become a nuisance in client-side dependent, heavily dynamic, Web 2.0, DHTML, AJAX type web applications.
• Themes discourage developers from learning more about web design and the technologies surrounding it. Themes offer a seemingly simple API, which shelters developers from the complexities of CSS and JavaScript, but sooner or later The Law of Leaky Abstractions comes into play and knowing the fundamentals of these technologies is a necessity.
• Professional web designers don't use ASP.NET Themes, CSS is the language of web designers.

Default Skins on the other hand can be useful for defining consistent CSS hooks into common ASP.NET controls. It's unfortunate that we can't use Skins without Themes.

Related posts:

• The Problems with Themes, Skins, and Cascading Style Sheets (CSS) - Where it all Falls Apart
• Excluding a CSS folder (Work Around #1)
• Defining a Media Type(s) (Work Around #2)
• Defining the Load Order (Cascades) for CSS (Work Around #3)
• Using Internal (Embedded) Style with Themes (Work Around #4)
• Creating Printer Friendly Pages (defining a CSS Print Media Type) with CSS While Using Themes (Work Around #5)
• A Resolution to The Problems with Themes, Skins, and Cascading Style Sheets (CSS) - Putting the Cascades back into ASP.NET 2.0 Themes (taking control over CSS Cascades / Load Order, Media Types, and Overrides)

This weekend I upgraded my blogging engine to dasBlog 2.0 from dasBlog 1.9 - well actually it wasn't even 1.9 it was ThinkJot - a source cut from dasBlog 1.9 that was "modified" to run on ASP.NET 2.0 in Medium Trust.

In order to say "Thanks" to the dasBlog team, I'm referencing the list of dasBlog contributers.

The dasBlog contributors are:

• Alexander Groß
• Ben Scheirman
• Clemens Vasters
• Erv Walter
• Gray's Matter
• Harry Pierson
• James Snape
• John Forsythe
• Joshua Flanagan
• Kris van der Mast
• Mark Michaelis
• Michael Earls
• Omar Shahine
• Paulb Vanbrenk
• Scott Hanselman
• Stephen Forte
• Steven Rockarts
• Tom Mertens
• Tom Watts
• Tony Bunce
• Torsten Weber
• Vasanth Dharmaraj

Thanks!

One of my new years resolutions is to become a dasBlog contributor... :)

Professional ASP.NET 2.0 Design: CSS, Themes, and Master Pages by Jacob Sanford is a great book for ASP.NET developers looking to expand their knowledge on the ASP.NET 2.0 Web Design front.

I've read this book, re-read it, edited it, and would like to give it away - I was the Technical Editor. The books is like new and (did I mention) it's free!

Contest Rules:

• Updated! Just Leave a comment with a valid email address!

• Post a 500 x 200 pixel image of something you're working on in the comments of this post - this image could be code, web design, or anything work related.
• Include an optional description of your work
• The winner will be chosen April 1st May 1st, they'll be drawn at random, and will be notified through email.
• I pay for shipping.

* I've included a sample entry in the comments. If you're looking for a great free photo editing application then try Paint.net. If you're looking to host your image you might want to consider Flickr or Photobucket.

Good Luck!

The contest has ended, and the winner is..... Andrew Hinde. Nice!

JavaScript is probably the world's most popular and misunderstood programming languages and for good reason - most developers will claim they know JavaScript even when they don't - I know I have!

When a developer claims to know JavaScript this generally equates to one or all of the following:

• "I know what JavaScript is, I can learn JavaScript in 30 minutes"
• "JavaScript is for kids, it's a toy language, it's easy"
• "I just copy and paste my JavaScript snippets / scripts from the internet"
• "JavaScript is just another programming language like C++, C#, VB.NET, or Java"

If thoughts similar to these have crossed your mind when sizing up your JavaScript knowledge, then you probably don't know JavaScript.

I would argue that if you've never programmed in a functional programming language (like: Lisp, Scheme, F#), never read a GOOD book on JavaScript, or never watched a video on JavaScript, then you probably don't understand JavaScript at all. JavaScript is starkly different than any other mainstream programming language.

When it comes to JavaScript, if you don't understand the fundamentals then you're only punishing yourself.

Here are some things every JavaScript developer should probably understand:

• JavaScript, Mocha, LiveScript, JScript, and ECMAScript are all essentially the same.
• JavaScript is a prototypically inherited (prototype-based programming) language which is very different than the classically inherited (class-based programming) languages like C++, Java, and most of the .NET languages - you know the difference between a prototype-based programming and class-based programming language.
• JavaScript is a loosely typed language - you know the difference between strongly-typed programming languages and weak-typed or loosely typed languages.
• JavaScript is a functional lambda language - you understand lambdas and that functions in JavaScript can be lambdas.
• JavaScript functions can be defined inside functions, inside functions, inside functions, and so on - you can demonstrate this.
• JavaScript uses function scope, has no curly brace '{}' block scope - you understand that this is common attribute of most functional programming languages.
• JavaScript has no private, public, protected assessors, no classes, no enums, no structs - you understand that all these language features can be achieved through objects and function closures.
• JavaScript is classless, but instead it uses objects as general containers.
• JavaScript makes use of garbage collection.
• JavaScript uses truthy and falsy values - you understand which values are truth and falsy.
• JavaScript makes use of the 'nan' (not a number) and 'undefined' values - you understand the difference between these values.
• JavaScript has pretty good debuggers - you understand how to debug JavaScript from both IE (link) and Firefox (link).
• You appreciate recursion, and understand that recursion is a useful technique in JavaScript.
  
• You understand that JavaScript Namespaces should be used - you understand the importance of namespaces, and know how to create one (Namespacing Your JavaScript).
• You know how to avoid the JavaScript pseudo-protocol (<a href="Javascript:alert('hello');"), and appreciate avoiding it.
• You know how to avoid embedding DOM Level 0 JavaScript events (<a onclick=''alert('hello');") in your mark-up / document structure, and appreciate this technique.
• You know that JavaScript can make use of two different event models (event capturing and bubbling), but we should only ever make use of bubbling.
• You understand what JSON is and how it's used.
• You know how to keep you JavaScript, CSS, document structure separate, and appreciate non obtrusive JavaScript.

If any of these points seem foreign, then it may be time to learn JavaScript. With all the hype and buzz around Web 2.0 and AJAX it could be a great way to augment your career while broadening your programming language vocabulary.

Great resources for learning more about JavaScript:

Videos:

• The JavaScript Programming Language: Part 1, Part 2, Part 3, Part 4
• An Inconvenient API: The Theory of the DOM: Part 1, Part 2, Part 3
• Advanced JavaScript: Part 1, Part 2, Part 3
• JavaScript: The Good Stuff: Link
• All these videos are available on the YUI Theater - all the videos are great, watch them all!

Books:

• JavaScript: The Definitive Guide (Paperback) by David Flanagan

Links:

• MDC: A re-introduction to JavaScript
  
• Code Conventions for the JavaScript Programming Language
• JavaScript: The World's Most Misunderstood Programming Language
• What ASP.NET Developers Should Know About JavaScript
• Best Practices: Implementing JavaScript for rich internet applications
• The seven rules of Unobtrusive JavaScript
  

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