Differences between ScriptRunner for Jira Server and Jira Cloud
As it is not possible to integrate directly into the standard search functionality that Jira Cloud provides, the ScriptRunner Enhanced Search functionality provides the ability to run advanced JQL functions on your Jira filters in a similar way to ScriptRunner for Jira Server. ScriptRunner for Jira Cloud follows the same principles as Jira Server, but the execution model is significantly different due to the differences in extension points between the Atlassian Connect framework used to write add-ons in the Cloud, and the Plugins V2 framework used behind the firewall for implementations. Atlassian Connect is also inherently asynchronous, which means that when a script executes, the user may see the page load before the script has completed.