Candy is a jQuery multi user chat client that features multiple rooms, private chat, new message notifications and tools for moderation & to control spam.
It requires a Jabber server with HTTP-binding but installation guides are provided. An apache server with mod_rewrite, mod_proxy and mod_proxy_http modules are also required.
It has several configurable options including a language pack which includes seven popular languages.
There are also plugins available in the official repository to extend the default functionality via event hooks.