We've taken Quplo's [Common Sense Code Completion][
(http://blog.quplo.com/2010/06/common-sense-code-completion/) and turned it contextual. Very neat for code editors in the cloud.
Short version: The guys from Quplo - http://quplo.com/ - added code completion to CodeMirror (javascript in browser editor). We made it context aware and improved the (x)html handling a bit. Here's the code: https://github.com/webpop/cscc