This is a list of syntax highlighters written in JavaScript I was able to find.
+ automatic language detection
+ says it doesn't interfere with embedded tags but works only sometimes
- recognizes embedded JS and CSS, not SQL
- quotes around JS and CSS attributes highlighted as part of value
- doesn't link documentation
+ optional line numbers
- reads code from TEXTAREA
- no languages embedding
- doesn't link documentation
+ several color themes
+ language definitions taken from GNU Source-highlight
- no CSS support
- no languages embedding
- doesn't link documentation
jQuery plugin
+ optional line numbers
- server side
- no languages embedding
- links only HTML and PHP documentation, sometimes wrong (iconv)