With input from TL, I'm creating a further stage after nextFreeId which will generate a location file from data entered into a form, based on a template. The form is set up and working, and I've spent some time experimenting with embedding the template as XML into an XHTML script tag, following documentation on the MDN site, but it seems like it will be difficult to treat this data both as XML for the purposes of injecting it and as text for the purposes of doing search-and-replace to insert the data. May have to resort to generating the file on the server and returning it to the user.