As far as I understand the Ajax-Plugin you need a Webserver to response => php - which is executed on the server.
For executing javascripts(which will be executed on the client) i've written a small plugin:
see it here: Plugin CallJS
if such local(on the client) script-execution is possible with the ajax-plugin let me know <img src="smileys/smiley2.gif" border="0" align="middle">
greets, Joe7