Comet or Long Loop message pattern

A while back I posted a possible solution to dealing with long running processes in a web application. While that solution works for very basic processes, the use of threading in an asp.net application can be the cause of a lot of grief (there are just too many ways outside of your control for those threads to be aborted prematurely).

I did a little research and came up with a MUCH better solution - simply execute the ajax request for the long running process, and then listen for messages on another ajax request. The key to this working, however is to ensure that your long running process is a SESSIONLESS request, otherwise your request will block further ajax requests until it's completed.

Javascript videos

If you are a web developer, you almost certainly need to program in Javascript.  If you need to program in Javascript, you need to watch this series of video presentations by Douglas Crockford.  

Hopefully most of you (web developers) know who Mr Crockford is, but for those that don't recognize his name: he works for Yahoo, and is a well known author and presenter on Javascript topics.  He is a member of the ECMAScript standards body and a general Javascript guru - developer of JSLint, the JSON spec and author of JavaScript: The Good Parts. 

These lectures were given to (some members of) the Yahoo development team.  The first lecture is a fascinating history of computing and language development which is really informative and sets up the other lectures (on Javascript) really well.  If you don't have the time for the first lecture you can dive in on the second one and get right into the language implementation details, but I really do recommend you start with the first video.  Each presentation is about 2hrs long, so make sure you've set aside enough time - it will be worth it!

I can't recommend this enough - if you're serious about your professional development as a web developer, Mr. Crockford's material is must-read and must-watch.