Digging into Jelly

The web's language is HTML. Every page rendered by a web browser has some HTML content. Therefore, the ultimate job of any website is to generate the HTML that contains data formatted in the desired manner. The browser then renders it and hopefully displays something beautiful, informative, and useful.

 

ServiceNow uses Jelly to generate HTML. The Jelly processor in ServiceNow takes in an XML template and produces HTML. There are a variety of Jelly elements, including variables, loops, and conditions, which means that the produced HTML depends on the data that the processor is fed. In addition, ServiceNow has extended beyond the standard Jelly tags, allowing JavaScript to be used inside a Jelly XML document while also incorporating caching. This makes it powerful and fast!

Note

The name Jelly was originally short for Java Elements. You can find more information about it at http://commons.apache.org/jelly. It is not something to eat!

While Jelly is very powerful, it is slowly...