AJAX :: Update Multiple Window Elements With Single Request?

The general outline is that I have part of a page that deals with the addition, editing and deletion of upcoming events. Data is stored in a MySQL table. The form design (in traditional terms) would be very simple requiring three fields, one for the Event Name, one for the Event Description and one (hidden) to identify the UniqueID of the event in the MySQL table. (As the reference to make edits.) The table therefore has 3 fields. (There are more such as Timestamp, clientID etc, but they are not important here.)

I envisage three functions, one to add, one to edit and one to delete the event listed on the page. I have 3 php files eventadd.php, eventedit.php and eventdelete.php which speak for themselves.However, this is where I have the problem. What I have been doing is returning the xmlhttpresponse as a formatted HTML page for the two 'form' elements because whilst I can return unformatted text containing the relevant fields in one response, I don't know how to break that down into two sections for the innerHTML of the two 'form' elements that change.

Returning a formatted page does work, but as well as being slower than neccessary, I am also running into character-set encoding issues and I just know that I am not doing this properly. I can supply code and things, but I have a feeling that this problem will have come up somewhere and probably has a recognized solution because to me it seems to be such an obvious requirement to be able to populate several form elements with fields from one recordset.