Processing a large (12K+ rows) array in JavaScript

http://square.github.com/crossfilter/ (no longer maintained, see https://github.com/crossfilter/crossfilter for a newer fork.)

Crossfilter is a JavaScript library for exploring large multivariate datasets in the browser. Crossfilter supports extremely fast (<30ms) interaction with coordinated views, even with datasets containing a million or more records...

This reminds me of an article John Resig wrote about dictionary lookups (a real dictionary, not a programming construct).

http://ejohn.org/blog/dictionary-lookups-in-javascript/

He starts with server side implementations, and then works on a client side solution. It should give you some ideas for ways to improve what you are doing right now:

• Caching
• Local Storage
• Memory Considerations