Deeply nested elements crash FF 8, Chrome 11

```
vytah said 

"""
OK, I didn't circumvent the protection, but I managed to crash Firefox 8 and 
make it unusable until I restarted it in safe mode.
My input was about 20000×<div> (opening only, no closing)
"""
```

Original issue reported on code.google.com by `mikesamuel@gmail.com` on 10 Oct 2011 at 9:20
