Thursday, June 7th, 2007

JsLex: Profile your Ajax applications

Category: JavaScript, Utility

JsLex is a tool to profile your Ajax applications:

Working on the Apache XAP project and Nexaweb’s Universal Client Framwework, which has a large code base it became apparent that hand injection of profiling code only worked so well. A new technique was needed to make it possible to capture a complete view of the performance of an Ajax application in a similar way to using jProfile for Java code.

You install the JsLex application and then add in the JavaScript library:


  1. <script type="text/javascript" src="http://localhost/jsLex/javascript/jsLex.js"></script>

At this point you can hit the JsLex app, and you get all kinds of metrics:


Posted by Dion Almaer at 8:18 am

4.2 rating from 24 votes


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this is very cool.

Comment by Mark Arrington — June 7, 2007

How does this differ from the profiler in Firebug?

Comment by Ryan Hicks — June 7, 2007

This profiler works both in firefox, mozilla, IE, safari, …

Many of the performance issues that people run into aren’t on firefox. The ability to use it on any browser allows users to touble shoot problems where they happen.

Comment by Robert Buffone — June 7, 2007

so it will work under IE6/IE7?

Comment by Charlie Cheng — June 7, 2007

It’s too much of a hassle for me to install, and Firebug’s profiler is “good enough” for me. That “Call Graph” button in the screenshot makes me curious though. I’ve been thinking for a while of whipping up some quick and dirty call graph generator (combining Firebug and Graphviz) myself.

Comment by Tim Cooijmans — June 8, 2007

Is there a user forum somewhere for jsLex?

Comment by Erik Ostermueller — June 8, 2007

Is there a possibility to compare my website with other websites?

Comment by Thomas Rosqvist — July 18, 2007

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