JIS is the Japanese Industrial Standard. JIS is the most used and, if possible, I suggest that you use it. Most Japanese enabled web browsers will automatically detect that the page is in JIS format and display the text in Japanese for you. To display the others (EUC and SJIS) you will have to tell your browser that the page is in Japanese and then it will determine which method is being used.
To use JIS on your webpage put this tag between the <Head> and </Head> part of your HTML.
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-2022-jp">
Example: the word Nihon in JIS is: にほん View example.