jim chessclock
I tried for a long time to get your chessclock to install within firefox.
(It would have been helpful if you'd given explicit instructions.)
After multiple frustrating rounds of renaming the .zip to .xpi and trying
Firefox's install, putting it various places within the profile
folder, trying various versions of chrome:// url's in the window,
all to no effect, I finally found a recipe that worked here:
namely
# -- ~/.profile --
# for Sam's work with mozilla development
export samfall2011=/Users/mahoney/academics/term/2011-09-fall/tutorials/sam
export firefox=/Applications/Firefox.app/Contents/MacOS/firefox
alias samfirefox="$firefox -profile $samfall2011/firefox_profile -no-remote "
(0) set up "samfirefox" command line alias as above
(1) put Sam's unpacked chessclock/ package anywhere
(2) create an extensions/ folder in the profile folder.
(3) create a text file named chessclock@samauciello.com
(id listed in one of the meta files) in extensions/
with one line of text: the full path to the chessclock/ package,
including the trailing slash.
(4) launch firefox with that profile folder
(5) visit url chrome://chessclock/content/clock.xul
(Note that is *not* the path to the clock,
which is actually chessclock/chrome/content/clock.xul ;
"content" here is one of several keywords apparently.)
I'll look at the actual XUL code another time.