Most efficient method of detecting/monitoring DOM changes?

To bring this up to date, the DOM4 standard does away with Mutation Events and replaces them with Mutation Observers: https://developer.mozilla.org/en-US/docs/Web/API/MutationObserver

http://www.quirksmode.org/js/events/DOMtree.html

jQuery now supports a way to attach events to existing and future elements corresponding to a selector: http://docs.jquery.com/Events/live#typefn

Another interesting find - http://james.padolsey.com/javascript/monitoring-dom-properties/

Mutation events are the W3 recommendation of what you are looking for..

Not sure if they are supported all around.. (IE will most likely not support them..)

You could try using the DOMNodeInserted and DOMNodeRemoved events. Acording to Quirksmode, they kind of work in most browsers, with the notable exception of IE...

http://www.quirksmode.org/dom/events/index.html