Extensions to Jelly syntax

Apache's Jelly syntax is used to render forms, lists, UI pages, and many other things rendered in ServiceNow.

With Jelly, logic can be embedded within static content and computed values may be inserted into the static content.

Attention: This functionality requires a knowledge of Apache Jelly (a Java and XML based scripting and processing engine for turning XML into executable code).

This page from Apache has a summary of the standard Jelly tags: http://commons.apache.org/jelly/tags.html