I would also love a simple indicator of which tabs are 'busy' consuming cycles or generating garbage, so I know which tabs to kill first to get back to acceptable performance. (Perhaps even just a rough indicator of how many setTimeout()s are originating from a page would be enough.)

I wish there was a simple way to suspend all open tabs. I really have no need to refreshing disquis-comments or some crazy scripts that track my mouse pointer to generate heat maps.

I even tried to write a little chrome extension which injects a content script into every open tab, which calls settimer to get the highest timer-id and kills all timers with ids from 1 to this id. But for some reason it didn't work.

Use the Chrome Task Manager. You can get to it via the Tools menu, or a keyboard shortcut (shift+esc on Windows).

s/love/love in Firefox/

...as I meant to imply by replying under an FF issue.

But speaking of Chrome, I'd prefer the activity indicator in the tabs themselves... mapping the Task Manager names to my many tabs distinguishable only by not-necessarily-unique favicons is a pain.

I'm curious if it will be possible to get this feature working in Firefox. Since other posts here indicate that this was possible for Flash because it is using the Pepper stack and since Firefox has said they do not plan to adopt Pepper (https://bugzilla.mozilla.org/show_bug.cgi?id=729481), I wonder how possible this will be.

This feature could significantly negatively affect Firefox's market share.

Shumway is a more direct route to solving this problem than reverse engineering the Pepper API. The Shumway approach has several other advantages too, such as portability and unifying the graphics/audio/JIT stacks of the browser and Flash. Assuming Shumway works out (that's a big assumption, but so is assuming that Pepper could be reverse engineered and shipped), I don't see any technical obstacles to Firefox doing this as well.

The bug indeed seems to conclude it's impossible until Flash is eradicated, though disabling Flash in anything but the foreground tab + click to play will probably make it moot. (Apparently Safari does exactly this)

There's alternatives such as Shumway.

Also, in my experience lack of Flash or it crashing is seen as a way bigger problem than nasty tabs, as of now.