Anyone know why Chrome (maybe Javascript) sometimes goes haywire when it sits in the background?

I'm one of those people who tends to have open tabs in my browser. Like, *lots* of open tabs. Like, 50 or more.

I'm not sure if it's a recent change, but the past week I've been noticing a tendency for Chrome to start chewing 50% of my CPU (that is, two cores) when I'm not doing anything. When I investigate, it always seems to be that two tabs that are *not* currently on top are each eating 25% of CPU. It's not the same tabs each time, but it does always seem to be "heavy" pages that are likely to be full of Javascript. The problem usually goes away simply by finding and clicking on that tab, bringing it to the front. My best guess is that the Javascript on these pages is getting into some kind of frantic loop, doing something that isn't allowed while it's in the background, but that's just a guess.

Anybody have any concrete ideas what is happening here? I ask mostly out of idle curiosity, but also because there may be an anti-pattern that I want Querki to avoid...

Heartbleed Explanation

For those who haven't already seen it, and were wondering about the "Heartbleed bug" that everyone was in a tizzy about this week, yesterday's XKCD comic gives an unusually clear and simple explanation of it, which can be understood even without much tech background. It's not even very metaphorical -- aside from the fact that you have to ask the questions in a formal way over the Internet, rather than by saying them, this is how it works.

Most security problems are kind of subtle, and require a measure of expertise in order to exploit them; this one is really dead-simple, and while it hands you back somewhat random data, that data is often fairly dangerous and useful. Hence this week's massive fire drill across the Internet, as everyone hastily fixed the bug...