Mozilla is the cross-platform, open developing, Unicode based open source of the next generation internet client. This paper discusses several algorithm we developed for Mozilla which related to Unicode and internationalization. We will first look at how we will support the basic upper /lower case conversion for the whole Unicode by using a table less than 1K bytes [Note- Based on Unicode 2.0]. Then, we will look at how we generate different id for CSS2 list-type, including greek, cjk-ideograph, armenian, hebrew, georgian, etc. We will also discuss some number generation algorithms for future work. Then, we will examine our Unicode based Hankaku to Zenkaku (Japanese half width kana to full width kana) conversion. Line breaking and word breaking issue / algorithms will also be discussed in this paper. At the end, a demo of the work will be presented to the audience.