These pages help you find out whether your browser correctly decodes certain character sets.
Manual Character Set Tests
These pages help you find out whether your browser correctly decodes certain character sets, but the testing is manual: You'll have to view the pages and compare to the reference images. You could also look at these pages to find out what characters are available for a given character set.
UTF-8 Pages with Reference Images
These pages have reference images so you can check the fonts on your system.
Character Code Finder
This allows you to copy text from somewhere else, and it will show you the UTF-16 codes in the text, with a few different output options.
Japanese Kana Generator
Advanced Japanese Kana Generator
This is an extended version of the kana generator above, allowing multi-line input and mixed romaji, hiragana, and katakana output.
Korean Hangul Generator
Korean Linear Hangul Generator