AJAX is often used in web applications without need. This is because it has become one of the latest buzz words
in IT. It would, however, work very well in HFS as it would allow refreshing of certain elements of the page (such
as the files list) without requiring the rest of teh page to be reloaded. Yes, javascript is a security risk. Yes, it
isn't essential. Did you pick up on the fact that web servers also can have security holes in them? Hell, your OS
itself (especially if you're running Windows) is littered with security holes. The best way to keep your system
completely safe is to just get off the internet.
But while we're on the subject of meaningless, WRONG statistics, check this page out, Maverick:
http://72.14.253.147/search?q=windows%20maliciousI think you'll find the value is quite alot higher than the value for javascript. Maybe you should switch OS's

The point of my post is, javascript and AJAX can provide a far greater benefit with their use than a drawback.
Keep your OS patched, keep your browser up to date and keep your code written well and you won't have any
problems any time soon.
Prawned.
Kthxbai