Steps to reproduce:
1. Open 2 blank tabs in IE.
2. In one of them navigate to this demo page: http://jsfiddle.net/MTJ27/15/ ; it runs 4 web workers in a loop.
3. Check the CPU utilization (on a 8-core machine it should show 50%, for 4 cores or less: 100%).
4. Close the tab that displays the demo page; leave the other tab open.
5. Check the CPU utilization again -> it doesn't drop! IE still runs these web workers (IMO).
It's a bug, isn't?
Regards,
Robert