Logged In: NO

You have to edit copy file /etc/xpdfrc to ~/.xpdfrc
(pdftohtml defaults read xpdf's config file from ~/.xpdfrc
and /usr/local/etc/xpdfrc)

zh_TW encoding includes "Big5" and "Big5ascii"
zh_CN encoding includes "ISO-2022-CN", "EUC-CN" and "GBK"