There is a list of supported browsers in the system requirements. If a browser is not in that list doesn't mean that this browser will not work - but You have to do do some testings. There are reports from users where firefox wirks fine - although not supported.
A webpage should be displayed - there might be elements that don't show properly, but this could be resolved using other methods/elements (i.e. radio buttons might not be good, but value lists are fine, etc.)
Short version: You have to try with some browsers! (the technet server will support one connection for webdirect)
** Sorry for typing mistakes - but it's impossible to edit postings on iPad here
Thank-you Markus for your very helpful information. I sounds like I should make the layouts as simple as possible and then test a lot. Good advice! Thanks again! Roy