IE8中最有可能导致Javascript错误的原因是什么？

I'm seeing a lot of Javascript errors in IE8 on pages which worked fine in IE7 (and Firefox, Chrome, and Safari). I know that IE made some changes to things like Javascript security. Some of these don't give clear error messages - things like cross-domain violations can end up throwing very vague exceptions.I'm seeing a lot of Javascript errors in IE8 on