Test Your Japanese Online

Hiragana and Katakana

http://www.realkana.com/

A simple website to practice Hiragana and katakana.

J-CAT self test

http://www.j-cat.org/en/

This is a website to test your Japanese level. It is convertible to Proficiency Level and JLPT level. You can use it online for free. And it automatically adjust the questions based on correct/incorrect answer you did for previous questions.