Scintillua enables Scintilla lexers to be written in Lua, particularly using LPeg. It can also be used as a standalone Lua library for syntax highlighting support.
The HTML lexer highlights both CSS and Javascript, provided they are within <style type="text/css"></style> and <script type="text/javascript"></script> tags, respectively. Or did you mean something else?
For example, highlighting JavaScript and CSS on HTML. Is it possible?