With this little helper you just pass your array and what you are looking for and it will return you back a result array, a typical use would look like this:
var searchResult = searchBinary("m", array, true)
the parameters are : searchBinary(search string, array to search, case insensitive?)
This will return an array with all items starting by the letter m. A good use of this script would be with a auto-complete widget.
For more informations: http://www.position-absolute.com/articles/optimizing-a-search-functionality-with-large-javascript-arrays/