Contrary to the previous post, I decided that the best way to submit a report query to the back-end is to build a URL search string; this will enable us to provide URLs directly to reports. The SQL query should be constructed by the back-end code based on the field values submitted (through GET). This is also consistent with our AJAX code in the Moses and ScanCan projects.
Created a JS file to do this (hcmc_reports.js). This will later include all the AJAX functions. Tested the search string generation, and tweaked the form field names so they make more sense as GET fields.