This example is an interactive web tool for querying empty classrooms at a university. It displays a form where users select a semester, week range, campus, and building to filter available rooms. The interface uses chained dropdown menus that update via AJAX calls to server endpoints like `/kjscx/querykclistbyxnxq` and `/kjscx/queryJxlListBySjid`, populated with JSON data. Results are rendered as a table, with validation requiring a semester and week selection before submission.