Anytime I say Netscape 6, assume I mean the newest version, or better yet, change Netscape to Mozilla (Since Netscape is just an AOL ad filled version of Mozilla).

Ture, Netscape 4.x programing can be a PITA, but if you can do it, you are a true webmaster :-) There are of course some things that NS4 simply can't do, but for anything beyond that, it should always work in both NS 6 and IE 6.

A few last tips, make the popup window be recycled instead of popping up a ton of them. And better yet, make it so clicking on a color will pop up a window. Then clicking on a second color will pop up a second window for a comparison. Lastly, recycle those two windows, bouncing back and forth every click.