If you don’t properly handle the inevitable errors in your web applications, you can expect your users to eventually react about like this guy. Since they typically squelch any server-side errors, AJAX service calls are especially problematic. In fact, they rarely even throw a client-side error when they fail.

Even when a client-side error is thrown, most users won’t notice it and the ones who do notice won’t know what the error means or what to do next. In fact, I’ve found that even many developers don’t notice client-side scripting errors that occur while they’re debugging their own applications!

To help you remedy this problem in your own applications, I want to show you one way that I handle AJAX service call errors with jQuery. To do this, we will build an error-prone web service, make an AJAX request to it via jQuery, handle the resulting server-side errors gracefully, and use a jQuery plugin to attractively present those errors.

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When working directly with JSON serialized ASMX services, be it via jQuery, pure XmlHttpRequest calls, or anything else other than the ScriptManager, one question inevitably arises. That question is of the inexplicable .d attribute that appeared in ASP.NET 3.5.

What is it? Why is it there?

In this post, I’ll use both a 2.0 and a 3.5 example ASMX web service to illustrate exactly what’s going on. I’ll also show you why it’s a good change.

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A common question that I find myself fielding lately is how to handle the problem of rotating JavaScript based advertisements. As AJAX becomes ubiquitous on ad supported sites, we must take care that decreasing page views don’t also mean proportionally decreasing revenues.

Many find their way to ScriptManager.RegisterStartupScript, use that to re-inject the script during a partial postback, and expect that doing so will refresh the ad. Unfortunately, that doesn’t work when dealing with JavaScript based ads such as Google’s AdSense.

In this post, I’m going to show you why RegisterStartupScript does not solve the problem, the alternative that I suggest, and how to use that method to also defer loading of advertisements until after your content.

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It’s hard to believe that nearly two months have already passed since opening the doors on the Username Availability Validator project. I made a few mistakes in how I ran the project, but I’m happy with the overall outcome.

However, one thing that disappointed me throughout the entire contest was how slow CodePlex can be. Even as the single person most invested in the success of the project, I often found myself leaving the site in the middle of tasks, unwilling to endure the slowness. What’s worse, I also found myself procrastinating to avoid returning to CodePlex and dealing with these waits.

I’m not one to complain without offering some constructive criticism though. Especially since we’re talking about a completely free service.

I think the lesson to be learned here is something that many ASP.NET developers could benefit from. So, I’d like to take a look at one ASP.NET AJAX related inefficiency that I found on CodePlex and one potential alternative to it.

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While reviewing my latest post’s outbound click-through stats, I noticed that most of you found Rik Lomas’ quickSearch more interesting than the rest. In light of that interest, I’ve decided to show you an example of how you might implement its functionality in conjunction with ASP.NET.

For this demonstration, I’m going to use Delicious as a source of sample data to apply the technique to. I’m sure you’re getting tired of my RSS feed as demo data, and the Delicious API provides an abundance of topical data via jQuery tag feeds.

In this post I will show you how to use LINQ to XML to query the Delicious API, display that data in a table, apply the quickSearch plugin to that table, work around a problem that arises when using quickSearch with ASP.NET, and lay the groundwork for a “no results” state.

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One of jQuery’s greatest strengths is its thriving plugin ecosystem. Hundreds of plugins are available at plugins.jquery.com alone, with even more hosted on author sites. If you think of a feature, chances are there’s a jQuery plugin to implement it in just a few lines of code (if that).

Having used jQuery with ASP.NET for over a year now, I’ve discovered that some plugins are more easily combined with ASP.NET than others. In fact, one popular plugin even fails completely when used with ASP.NET AJAX.

Without further ado, here are seven of my favorites. I couldn’t begin to rank them preferentially, so I ordered them by how long I’ve been using them with ASP.NET.

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After the previous example of integrating jQuery and ASP.NET AJAX to display modal progress indication, there were requests that I follow it up with an example of also displaying the confirmation modally. So, I’m going to expand the original post with a technique for doing exactly that.

If you missed my first post on the topic, do be sure to read it first. Otherwise, this continuation may be difficult to follow.

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If you’re reading this, you probably already know that I’m a big fan of integrating jQuery with ASP.NET. If you’re of the same mind, you’re sure to enjoy the latest Alt.NET Podcast: jQuery in ASP.NET.

Update: Part two of our discussion on jQuery and ASP.NET.

Mike Moore hosted a roundtable discussion on the topic, between Bertrand Le Roy, Chris Brandsma, Rick Strahl, Steven Harman, Scott Koon, and myself. Between us all, the discussion ranges from the official Microsoft viewpoint, to theory about JavaScript and jQuery, to the pragmatic.

Whether you’re already on board with jQuery + ASP.NET integration or you’re still trying to figure out what the announcement means for you, I think you’ll find the discussion interesting. I know I did!

In the spirit of Microsoft’s official embrace of jQuery last week, I’d like to show you an example of how easily you can add jQuery functionality to existing ASP.NET AJAX applications. jQuery allows you to achieve exceptional results with minimal difficulty, and integrating it with ASP.NET is not an exception.

My previous posts about jQuery have been somewhat lower level, incorporating JSON, web services, and the like. While these are important tools to have at your disposal, the realities of software development sometimes leave us scrambling for something quick and dirty.

In those situations, you may find yourself using the UpdatePanel.

To that end, I’m going to show you how easily you can use jQuery’s BlockUI plugin to display a modal progress indicator during an UpdatePanel’s partial postback.

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You have probably already read the great news that Microsoft is going to begin shipping jQuery with Visual Studio and ASP.NET MVC. If not, make sure you take a minute to read the official announcements from both ScottGu and John Resig. This represents a surprising, yet tremendously welcomed change of course for Microsoft.

If you haven’t yet used jQuery with ASP.NET, you’re in for a pleasant surprise. It removes almost all of the pain from client-side development. Coming from an ASP.NET centric perspective, you may find several of my previous jQuery articles useful.

Additionally, I highly recommend the articles that Matt Berseth and Rick Strahl have written on the topic of using jQuery with ASP.NET. I am constantly amazed at the quantity and quality of content that they both generate.

Introductions aside, I’d like to take this opportunity to discuss an incompatibility between ASP.NET AJAX and at least one jQuery plugin, which needs to be fixed.

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