When I disable "open unrequestet windows" in Preferences/ Advanced /Script & Windows I cant get Java-Script alert popups too. Thats bad. I want see those alerts, but I want no popup windows. In Mozilla, I can get Java-Script Alerts when I have "open unrequestet windows" enabled.
This is intended behavior. Not a bug.
asa's comment is not quite right. Read Dave Hyatt's comment in the Mozillazine general forum under the topic: does alert(); Work in Phoenix 0.3 This is a Mozilla back end bug: see bug #167559 Leaving the bug as invalid (too much spam to move it to duplicate)
Mass-verifying of old bugs.