Jelly is certainly a lesser known language to script in. It does not appear in the majority of ServiceNow, only on the outskirts of the platform. However, if you want to create custom pages in ServiceNow, it is a must to learn.
It is unfortunate that Jelly is a lesser known language, as documentation on how to use it is therefore also in short supply. Using pages already created in Jelly or the ServiceNow community can be very useful when getting started due to this general lack of information in the developer space.
One of the main areas you will find Jelly script is in UI pages, which we'll take a look at later in the chapter. Jelly code is found in XML field types, as it is a Java and XML scripting engine that allows XML to be turned into executable code.
When looking at Jelly script, you will see that it is almost always started and finished with the same tags. Let's have a look at this code:
<?xml version="1.0" encoding="utf-8" ?> <j:jelly trim="false" xmlns...