If a form script is loaded using an XHR from a web server, it is executed using eval().To debug it, you need to use browser-specific debugger extensions.

Debugging Form Scripts in Google Chrome

If you are using the Google Chrome debugger, you can add the debugger; directive to the sourcecode of the script:

  1. <form role="form">
  3.   <script cam-script type="text/form-script">
  4.     debugger;
  5.   </script>
  7. </form>

原文: https://docs.camunda.org/manual/7.9/reference/embedded-forms/javascript/debugging/