I've never seen the "Window-target" protocol. What I have done to get the same result is call up a dynamically generated frame set that has the new window... That is, my form has an IF-THEN-ELSIF (or SWITCH-surrogate) structure to select which frameset information gets printed to the browser. (Using cgi.pm, of course.)

In my particular implementation, however, this worked only for the IE browser. (This was an all CGI section -- nothing was static, and Netscape doesn't seem to like frameset.cgi putting other CGIs into the child frames, while IE survived.) You could most likely overcome this problem, but I was working on an Intranet where everyone (except me) used exclusively IE, so it wasn't worth my time...