Playing with these types requires good JavaScript skills. All too often you see in Google searches coders showing dependance on JQuery or equivalent.
Here is a cross broswer compatible suite of functions which allow manipulation of a select boxoptions. Built into the example is a suite of testing functions to demonstrate the usage of the functions.
The functions here are based in part upon the examples laid out from mredkj.com ( http://www.mredkj.com/tutorials/tutorial005.html )
== The JavaScript ==