Originating in Microsoft Research as Ajax View, the Visual Studio 2008 AJAX Profiling Extensions Power Tool was released today (download here).  It’s a JavaScript performance profiler with a novel approach: it modifies the code sent by your server to include diagnostic code to trace and time function execution.  The client browser then sends profiling data back to your server for aggregation and analysis as the JavaScript executes.  Once you’ve collected your data, you can install the power tool extensions for VS2008 Team Developer or Team Suite to view and analyze the results using the Visual Studio Profiler’s UI.

The benefit of the server-side instrumentation approach is that it works with any client browser, letting you see how various browsers affect your performance.  On the server, you must be running IIS7 with an integrated pipeline.  Currently, running this power tool on production servers is not recommended.

Between this power tool, the built-in IE8 JavaScript profiler, and the integration with Visual Studio, we hope to shine much needed light on client-side browser performance.