To run JChar Converter (and to browse this web site) correctly, your system needs to be able to DISPLAY Japanese characters on your browser.
To enable it, all you need is ideally to install Japanese fonts into your system.
Depending on your operating system or your web browser, this is done automatically when you open this web site.
When you open this web site:
Again, your system/web browser only needs to DISPLAY Japanese characters; not to TYPE Japanese characters.