I'm sure most people know this, but for those who don't. You can get a feature (plug-in) with Mozilla Firefox that allows you to view a web page with either Firefox or Internet Explorer.
Go to the lower right hand corner of the Firefox browser (only if plug-ins are installed) and click the icon. It will change to IE or if IE is showing it will change to Mozilla Firefox.
Handy for Web Developers.
Bookmarks