If you’re like me, HTTP status code 200 Object] unknown probably doesn’t ring any bells. Of course, that’s mainly because it doesn’t exist.

So, how did I end up with the screenshot above? I’ve been running with scissors again. It was one of the more popular web frameworks for Node.js that I cut myself with this time: Express.js

Unfortunately, a malformed status code like 200 Object] will cause some browsers (including the version of Chrome I was using at the time) to refuse loading the page at all. That quickly elevated the importance of my strange status code from a trivial oddity to an annoying thorn in the side.

As it turns out, my code was running up against a documented Express feature and the remedy was simple enough.

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For the past week, I’ve been neck-deep in a challenging project that combines jQuery Mobile and PhoneGap to do some relatively heavy lifting. Though I’ve used both jQuery Mobile and PhoneGap in the past, this recent exercise left me with a few morsels of newly-hard-earned knowledge. Among that education was learning that PhoneGap 1.1.0 breaks jQuery Mobile’s back button on Android devices.

Being able to use a web-based framework like jQuery Mobile to create a “native” mobile app is one of PhoneGap’s most appealing propositions. So, you can imagine my dismay when wrapping this latest project in PhoneGap broke its navigation. Worse yet, even closing jQuery Mobile’s dialog windows stopped working under PhoneGap 1.1.0.

Luckily, the problem ended up being a minor one with a simple fix. In this post, I’ll briefly show you why PhoneGap 1.1.0 caused jQuery Mobile’s back buttons to stop working and how you can fix that problem in your own app.

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I’ve been experimenting with Tomasz Janczuk’s awesome iisnode project lately, in hopes of hosting some of my Node.js sites on IIS. Those sites are running well enough on an Ubuntu VPS currently, but the features that iisnode offers are compelling (and I have unused capacity on one of my Windows servers).

Along the way, I ran into one issue that isn’t addressed in the current iisnode documentation or examples very well. If you try to set up a standalone Node.js website in IIS you’re likely to be greeted with this error when you load it up for the first time:

Remotely, you’ll see the dreaded “The service is unavailable.” error:

Those nondescript errors don’t exactly make resolving the problem very straightforward. So, I want to recap what I found to be the underlying problem in my case and a few solutions, in hopes of helping anyone else that ends up with the same issue.

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Over the past several months, I’ve been participating as an adviser to an interesting Microsoft patterns & practices effort named Project Silk. I don’t publish posts here about every project I’m tangentially involved in, but I think Project Silk is worth a look if you’re building modern, JavaScript-heavy web applications.

The project itself is comprised of a complete reference application and an extensive set of documentation describing how the app works and the process behind the design decisions that the team made along the way. Think of it as the NerdDinner sample (and accompanying book chatper), but focused almost entirely on client-side development rather than the server-side MVC component.

One of the most valuable aspects of the project is that it takes aim at the almost intractable topic of building large, maintainable JavaScript applications. You can see how seriously they took that goal by the time you get to just the second paragraph of the project summary:

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One of the most persistent misconceptions about ASP.NET’s page methods is the notion that they have some intrinsic protection against requests that don’t originate from the page where they’re defined. Since a page method’s code resides within a page’s code-behind file, it’s intuitive to assume that those methods benefit from some form of inherent security.

Unfortunately, that is not the case.

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When you’re developing client-side applications, a problem you’ll almost inevitably have to deal with is how to work with services that reside outside your website’s domain. Though many modern APIs do support JSONP, which is a clever workaround to somewhat mitigate the cross-domain problem, JSONP has its own problems.

Worse, if you encounter an API with no JSONP support, the cross-domain barrier can quickly become a formidable one. CORS is slowly becoming a viable alternative, but it requires that the remote service support it via special HTTP headers and browser support for CORS is still not ubiquitous.

Until CORS is more broadly supported, an alternative solution is to bounce cross-domain requests through the web server that hosts your website. In ASP.NET, the best tool for implementing that sort of middleman endpoint is the HttpHandler.

In this post, I’ll show you how to create an HttpHandler to service cross-domain requests, how to use jQuery to communicate with the handler, and an example of one improvement that this approach makes possible.

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They aren’t the most glamorous projects, but thousands of developers have integrated my Highslide JS .NET and PostBack Ritalin controls into their sites and applications over the years. PostBack Ritalin was even included in Subtext at one point. It’s definitely a great feeling to see your work put to good use (in fact, this motivator can be even more powerful than monetary gain).

As jQuery has risen in popularity among the ASP.NET community, both controls seem somewhat superfluous to me, yet they have surprisingly remained very much in-demand. As long as people are using them, keeping them working and bug-free(ish) is something that I’ll continue to pursue.

I wouldn’t mind some help though.

Over the years, I didn’t keep the source code for these controls closed due to any illusions of ever turning them into commercial products. Rather, they were the first server controls I had built for general consumption and the quality of their code is not great. For the same sort of reasons that developers “go dark”, I always preferred to keep that code hidden in my junk drawer.

At this point though, keeping their source hidden just to protect my delicate programmer-pride is counterproductive, so I’ve open-sourced both controls on GitHub. Go forth and fork them – pull requests are welcomed.

Fork PostBackRitalin on GitHub

Fork Highslide JS .NET on GitHub

A reader contacted me this weekend to inform me that jQuery 1.6.2 had broken all of my old examples of using jQuery with ASP.NET services. Not good! How could such a simple update have caused this?!

I didn’t really expect that updating from jQuery 1.6.1 to 1.6.2 would break anything, much less break everything.

As it turns out, the problem didn’t have anything to do with jQuery 1.6.2 or my own code. However, while investigating, I ended up falling prey to the same treachery that led to the original bug report.

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Mea culpa: I may owe your fingers an apology.

If you’ve been using my approach for directly calling ASP.NET’s JSON-based services with jQuery, you know that specifying the correct Content-Type on your requests to them is a crucial part of coaxing JSON out of them. However, when I suggested that a Content-Type of application/json; charset=utf-8 was necessary, that was overly specific.

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With the confusion surrounding jQuery 1.6′s changes to .attr() and the addition of .prop(), one of my favorite new features nearly slipped under the radar. The feature I’m referring to is that $.map() now works against plain JavaScript objects in addition to arrays.

$.map() has always been a useful utility method, somewhat mimicking ECMAScript 5′s native Array.map() method. If you’ve been working with JavaScript long, you’re probably already comfortable with passing anonymous function callbacks around anyway, which makes higher order functions like map an intuitive way to write concise, expressive transformation code.

With jQuery 1.6, now you can use the same approach when working with regular JavaScript objects. There are a variety of uses for this, but I want to focus on one real-world usage in this post: extracting an array of the keys contained within a JavaScript object.

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