Very handy Javascript memory leak detector

I used this tool recently and found it to be very helpful in detecting memory leaks related to closures and circular references (between JS and DOM). 

http://blogs.msdn.com/gpde/pages/javascript-memory-leak-detector.aspx

I have found that many memory leaks are a result of one of the following scenarios:

1. An event handler attribute on a DOM element references a javascript function which "closes" over a reference to the same element. This sets up a circular dependency and prevents both the JS and DOM garbage collectors from doing their job fully.

2. When using a virtual closure technique like the one described here: http://laurens.vd.oever.nl/weblog/items2005/closures/ the "sender" (e.g. "this") object can have a property referencing the DOM element with the event that is being subscribed to. In this case, a similar circular reference is created.

Developers should also take precautions when it comes to using the onreadystatechanged event of an XMLHttpRequest object. If the handler is a closure that closes over a reference to the same XMLHttpRequest object, another circular dependency can be created. This isn't necessairly detected by the above tool because the object is not part of the DOM.