You use function rules in online-only applications to define Java methods that run
when a function rule is processed. When you develop an application that users can access with
an offline-enabled mobile app, the mobile app uses JavaScript-based equivalents of Java-based
utility function rules, provided that such equivalents exist.
The function rule logic of JavaScript is equivalent to the logic of the Java version of
the utility function rule. However, not all functions that are available in Java are available
by default in JavaScript. Utility functions are available in several libraries. Therefore, to
find out which functions are available, you must read the documentation that is part of the
JavaScript text file rule for each of the libraries. For more information, see Offline-supported function rule libraries and Accessing a list of supported JavaScript functions for a utility library.