Sonadier has a Custom Scripting API for creating JavaScript scripts that run when a submission form is opened on the page. Change field values, create custom alerts, or make third-party requests. Scripts run each time a submission is initialized, and can access their submission with the self variable. Scripting is included with our Development Plan.
Writing Scripts
From the Form Editor, click the Scripting option in the menu bar at the top. Paste or write your script in the editor, and save it with the Save Form button in the top right.