FileMaker Server root web index file
This file that can be placed in the root folder which detects when the back button is pressed in the web browser and displays a customized alert warning the user that the back button is disabled for this application. This alert is only active while they are within the WebDirect session on this server, and stops once they navigate away to another website. Share your issues and suggestions there to improve the file.
Place the index file in the FileMaker Web Server Root. The default web server root is located here, https://help.claris.com/en/server-help/content/hostsite-fmwd.html:
Windows: [drive]:\Program Files\FileMaker\FileMaker Server\HTTPServer\conf
macOS for HTTP URLs: /Library/FileMaker Server/HTTPServer/htdocs
macOS for HTTPS URLs: /Library/FileMaker Server/HTTPServer/htdocs/httpsRoot
Linux for HTTP: /opt/FileMaker/FileMaker Server/HTTPServer/htdocs
Linux for HTTPS: /opt/FileMaker/FileMaker Server/HTTPServer/htdocs/httpsRoot