Solved: Blacklist IP won't save in JComments 2.3.0
Had an interesting issue when trying to add a spammer's IP to blacklist in JComments to disable comments from that IP. Upon saving the added IP nothing happened, the page just blinks but no IP gets added to the blacklist.
The solution could be found on JoomlaTune's forum and goes like this:
1. Open administrator/components/com_jcomments/admin.jcomments.blacklist.php
2. On line 291 change
if (document.adminForm.email.value == "")
if (document.adminForm.ip.value == "")
3. Save & try adding an IP to the blacklist again, should work now.
Worked for me!