Jelly scripting

Jelly scripting knowledge is important to build custom pages and scripts, and also to amend Jelly code that exists in ServiceNow as part of the platform to work in a different way for your own purposes. We introduced Jelly scripting and how it can be used in a UI page in the last chapter. Let's remind ourselves what the Jelly tags ServiceNow gives us look like:

<?xml version="1.0" encoding="utf-8" ?>
<j:jelly trim="false" xmlns:j="jelly:core" xmlns:g="glide" xmlns:j2="null" xmlns:g2="null">

</j:jelly>

Once these tags are in place, we can start to include our Jelly code inside. This can be added to a UI page or UI macro. We will take a look at UI macros later in the chapter.

Evaluate

First, let's have a look at the <g:evaluate> tag. This tag allows us to write JavaScript inside the tag and set a variable value at the end, if required. 

The <g:evaluate> tag is arguably the most used tag in Jelly, and is certainly one to get to grips with. Remember...