Guess what? If the script in question is buggy for whatever reason and causes an infinite loop or is otherwise waiting for something that will not happen in a short time, Firefox will give you a very similar warning with the same options to let it run or terminate it immediately.
The 'solution' is NOT 'switch to Firefox', unless of course you prefer the way it looks or works over IE, Chrome, Safari, Opera, etc. Just like the solution is not 'buy a Mac'. It's not the browser's fault that a Javascript script is buggy.