Yes. Visit here:

https://www.japanair.com/e/jmb/members/login_book.php

to log into your JMB account (assuming you're JMB Americas region). After you do, move your mouse pointer over "Redeeming Award" (on the left hand menu). You'll then see some menu options which you can select to obtain JMB awards online.

The functionality is somewhat limited, though. For example, upgrade awards and airline partner awards are not available online.