I used “Mozilla Firefox” to browse this page:
http://db.math.ust.hk/mainpage/e_main.htm When I got in there, it alerted : “Your browser is Netscape 5.0(Windows;zh-TW). To have a better view of this site, we suggest you to use Netscape 7.0 or above.”

I think Mozilla Firefox is newer than Netscape 7. I suggest you to check other information of browser like appCodeName or userAgent to decide alert the message or not. Although it is a small problem, I think many users of Mozilla feel strange when I saw it first time.