I wrote this description somewhere early in 2000 and hardly updated it since that time.
Although little used, Opera 3 is an excellent browser if you accept its weaknesses. First of all it does not support DHTML. Secondly, there are some minor but irritating inconsistencies with Netscape and Explorer.
Opera 3 cannot reload just one frame, it has to reload the whole window. Opera also has trouble with executing a cross-frame mouseover. Maybe Opera's handling of frames is fundamentally different from Netscape's and Explorer's.