The WWWJDIC Firefox plugin should now be ready to install.
Go to the Search option on the Firefox Navigation bar and drop down the menu of available search sites. You should have an option labelled "Add WWWJDIC". Click on that and the plugin will be active.
The plugin has been updated to use the new Monash site. It works OK with Firefox 40. (See below for Linux comments.)
I hope this is useful.
[I could not get the revised plugin to be recognized by my old (V20)
version of Firefox on my Linux system. I eventually installed it
manually by copying it into: