I've never used (or heard of) XSitePro. The editor usually shouldn't make a difference, though. But if however the software changes things in your code, it's time to find a new one.
A lot of people hate Frontpage (I've never used it), but after everything I've heard I wouldn't even bother trying it.
Take a look at this thread for some suggestions:
http://www.programmingtalk.com/showthread.php?t=47991
And there's no problem with previewing the script on your computer. Maybe try creating a blank page in notepad, and copy and paste the code in there, then save it as "something.html" and open it in your web browser. If that doesn't work either, chances are that you haven't enabled Javascript on your browser?