Xuheki is a web-based IMAP client written in Perl. It is completely build upon Ajax technology, i.e. there are no page reloads. Xuheki is released under the GNU General Public License. It uses persistent IMAP connections. The IMAP operations are not handled by the webserver itself, but by a Perl daemon which maintains connection to the IMAP server.
Currently it supports only the Apache webserver and the installation script is written for Debian/Ubuntu based systems. It might nevertheless be easy to install it on every Linux system.