The exhibits on that page seem to be quoted from https://msdn.microsoft.com/en-us/library/bb250448%28v=vs.85%... which is a 10-year-old article that was marked as obsolete 4 years ago. And it's specific to old IE versions; the problems are fixed in newer IE versions. And even in IE6 as of 2012; see https://support.microsoft.com/en-us/kb/929874

Back in 2005 Gecko (Firefox) had issues like this too, but a cycle collector was added in 2006 that handles this sort of problem.

For DOM nodes issues like this basically don't happen in modern browsers.

There _are_ still some existing bugs of this sort in browsers for objects other than DOM nodes (especially WebKit and Blink; modern IE and Gecko are way ahead here, though Blink is actively working on fixing this in their implementation). But you typically have to work quite a bit to hit these cases; all the common cases are handled correctly because otherwise pretty much any web site you left open for an hour or two would use up all the RAM on your machine.

I do agree that if you have to worry about compat with old/unpatched browser versions then you run into some serious problems with this sort of thing. If you have to deal with that, you have other serious problems too, of course.

And, again, the source of all the "leak while the website is live" behaviors I have seen recently is websites doing things like sticking more and more stuff in global arrays. That's just a basic no-no in a garbage collected language, obviously.

IIRC it was particularly hard for MS to improve on (got much better starting with IE8)... I worked on an extjs app around 09 that would just eat itself in IE6 (the corporate browser at the time) if the app was open more than 3-4 hours. It was pretty bad.. FF didn't have any issues at the time, and could run open all day. Even then, still much better than the late 90's, when the NN/IE4 browsers were still hanging on, and needed to be supported... that was anti-fun.