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IE7 JavaScript Improvements

By Dean Edwards | September 21st, 2006 | Filed in Browsers, DOM Scripting TF, Microsoft, Microsoft TF

The IEBlog recently reported some improvements in IE7’s JavaScript engine.

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The IEBlog recently reported some improvements
in IE7’s JavaScript engine:

We have heard a lot of requests to improve our Jscript engine, especially now that AJAX
sites are becoming more prevalent on the web. I want you all to know that we have been
listening and have recently made some great fixes to our engine to improve the garbage
collection routine and to reduce unbounded memory growth.

This was confirmed by tests performed by the qooxdoo developers:

In fact many demos of qooxdoo
run much faster now in IE7 compared to IE6. And they are even faster than in Firefox 1.5 in many cases.
This is a huge jump in performance. Microsoft did not tell about their exact modifications, of course.
Anyway, they have fixed the major problem of large JavaScript-based web applications. This problem,
despite having a catchy name, was mentioned many times before like
here and
If you have many objects created, which are simply accessible in the current scope, all
methods and features of JavaScript slow down dramatically.

It would be great if these bugs were fixed so I emailed
Chris Wilson for comfirmation. He replied:

Yes, it is true we’ve done some dramatic improvements to JavaScript
performance. I wouldn’t say we’ve fixed everything, but we’ve addressed
a bunch of memory leak problems and most significantly, taken a
different strategy for the Jscript garbage collector. This last one
makes a huge difference in many current JavaScript-heavy pages.

Good news indeed.

Your Replies

#1 On September 21st, 2006 11:18 am