Getting to know what added a specific element, removed it or changed its attributes requires some way to stop the script execution right at the statement where the change happens.
Should be pretty unlikely, yes. The new DOM bindings just change which native is called when open() and send() happen, which should not affect JS stacks, generally... Jan, can you find a one-day regression range for this?
So better solution could be split Scratchpad window on code part and message part. Switching between two windows/tabs (console and scratchpad) is bit annoying.
An undefined variable cannot be referred directly. However, all global variables are attributes of the same name of the global context (window in case of browsers), and accessing an undefined attribute is fine.
This post was written by David Mandelin who works on Mozilla's JavaScript team. Firefox 3.5 has a new JavaScript engine, TraceMonkey, that runs many JavaScript programs 3-4x faster than Firefox