Attribute: field

The field attribute, when added to the sys:xform-user-update tag, allows you to specify which field of the selected form you would like to be used in reporting that users have visited the page in question.

In specifying the desired field, you must indicate its ID number, which can be found listed in the selected form's "Settings" tab, accessible within the XForms administration by clicking on the "Edit" icon in the selected form's row of the "Forms" table.

Back in the desired page's "Source" editor window, simply enter the tag, along with the attribute and proper field ID, and the outcome should look something like this:

<sys:xform-user-update field="D125" />