HTML to XML

Yes. You can do that. Just take the user input and convert it into a valid xml document. How you go about this exactly will depend on the server side technology you are using, although most languages have a library (often built in) with good support for xml parsing/writing.

 

elppa actually answered your question as far as it can be answered given the information you have provided. How you go about this is dependent on your server-side technologies...

For example, if you can use PHP on your server, google "PHP, save as XML" and you will find a handful of tutorials. The link below looked pretty good:

http://www.dynamicdrive.com/forums/showthread.php?t=14165

you already mentioned JQuery. You can also use that to format and prepare your XML, then save it via PHP.

Of course, if you have a CMS already, why are you saving files to disk? It would be better to use your CMS's API and save this content into a database table.

 

no..well technically yes, you don't have to use php, BUT you do have to process it somehow.

Though it doesn't return xml, the closest thing to automatic processing is probably using PHP's json_encode function.