+Internal notes:
+
+This component creates two JS functions: process(), which starts the
+submission process, and start_job(), which starts the job on the
+server side.
+
+process() does the following:
+- disable the form submit button
+- for all form fields named in "fields", collect their values into an array
+- declare a callback function "myCallback"
+- pass the array and callback to start_job()
+
+start_job() is an xmlhttp standard function that turns the array of values
+into a JSON string, posts it to the location given in $action, receives a
+job number back, and then invokes the callback with the job number as an
+argument. Normally, the post target script will use FS::UI::Web::JSRPC to insert
+a queue job (with the form field values as arguments), and return its
+job number.
+
+myCallback() opens an Overlib popup containing progress-popup.html, with
+the job number, form name, and destination options (url, message, popup_url,
+error_url) as URL parameters. This popup will poll the server for the status
+of the job, display a progress bar, and on completion, either redirect to
+'url' or 'popup_url', display 'message' in the popup window, or (on failure)
+display the job statustext as an error message. If 'error_url' is specified,
+the "Close" button in the popup will then redirect the user to that location.
+