Scripting in ServiceNow is a fundamental skill for system administrators and developers that enables customization and automation of platform functionality. ServiceNow primarily uses JavaScript as its scripting language, allowing users to extend out-of-the-box features and create tailored solutions…Scripting in ServiceNow is a fundamental skill for system administrators and developers that enables customization and automation of platform functionality. ServiceNow primarily uses JavaScript as its scripting language, allowing users to extend out-of-the-box features and create tailored solutions.
There are two main categories of scripts in ServiceNow: server-side and client-side. Server-side scripts execute on the ServiceNow server and include Business Rules, Script Includes, Scheduled Jobs, and UI Actions. These scripts interact with the database and perform backend operations. Client-side scripts run in the user's browser and include Client Scripts, UI Policies, and UI Scripts, which enhance user interface interactions and validate data before submission.
Business Rules are among the most commonly used server-side scripts. They trigger when records are inserted, updated, deleted, or queried, allowing administrators to automate processes and enforce business logic. Script Includes provide reusable code libraries that can be called from other scripts throughout the platform.
Client Scripts respond to user actions on forms, such as onChange events when field values change, onLoad events when forms open, and onSubmit events before form submission. UI Policies offer a code-free alternative for simple client-side requirements like making fields mandatory, visible, or read-only.
The GlideRecord API is essential for database operations, enabling scripts to query, create, update, and delete records. GlideSystem (gs) provides utility methods for logging, user information, and system properties.
Best practices for ServiceNow scripting include using appropriate script types for specific needs, avoiding global Business Rules when possible, leveraging Script Includes for reusable code, and thoroughly testing scripts in sub-production environments. Understanding the execution order of scripts and their impact on system performance is crucial for maintaining a healthy instance. Proper scripting skills enable administrators to deliver efficient solutions while maintaining system integrity.
Scripting in ServiceNow - Complete Guide for CSA Exam
Why Scripting in ServiceNow is Important
Scripting is a fundamental skill for ServiceNow administrators and developers because it allows you to extend the platform's capabilities beyond standard configurations. While ServiceNow offers many out-of-the-box features, scripting enables you to automate complex business processes, manipulate data dynamically, and create custom functionality tailored to organizational needs. Understanding scripting concepts is essential for the CSA exam as it forms the foundation for more advanced development work.
What is Scripting in ServiceNow?
ServiceNow uses JavaScript as its primary scripting language. Scripts in ServiceNow run either on the server-side or client-side, depending on where the logic needs to execute.
Server-Side Scripts: • Business Rules - Execute when records are inserted, updated, deleted, or queried • Script Includes - Reusable server-side code that can be called from other scripts • Scheduled Jobs - Scripts that run at specified times or intervals • UI Actions - Add buttons, links, or context menu items to forms and lists • Access Control Scripts - Advanced conditions for security rules
Client-Side Scripts: • Client Scripts - Run in the user's browser when forms load, change, or submit • UI Policies - Control form field behavior (can include scripts for complex logic) • Catalog Client Scripts - Specific to Service Catalog items
How Scripting Works in ServiceNow
GlideRecord is the primary class for database operations in ServiceNow. It allows you to query, insert, update, and delete records.
Example of a basic GlideRecord query: var gr = new GlideRecord('incident'); gr.addQuery('priority', 1); gr.query(); while (gr.next()) { // Process each record } Key APIs to Know: • GlideRecord - Database operations • GlideSystem (gs) - System functions like gs.log(), gs.getUser() • GlideForm (g_form) - Client-side form manipulation • GlideUser (g_user) - Client-side user information • GlideAjax - Asynchronous server calls from client scripts
Business Rule Types: • Before - Runs before the database operation (good for data validation) • After - Runs after the database operation (good for related updates) • Async - Runs after the operation, in a separate process • Display - Runs when a form loads, used to add information
Client Script Types: • onLoad - Executes when the form loads • onChange - Executes when a specific field value changes • onSubmit - Executes when the form is submitted • onCellEdit - Executes when editing cells in a list
Exam Tips: Answering Questions on Scripting in ServiceNow
1. Know the difference between server-side and client-side: Server-side scripts have access to GlideRecord, while client-side scripts use g_form and g_user. This distinction is frequently tested.
2. Understand when to use each Business Rule type: Before rules for validation and data manipulation prior to saving, After rules for cascading updates to related records, and Async for operations that should not delay user response.
3. Remember the 'current' object: In Business Rules, the 'current' object represents the record being processed. In Client Scripts, use g_form to access field values.
4. GlideAjax is the bridge: When client-side scripts need server-side data, GlideAjax calls Script Includes. This is a common exam topic.
5. Script Includes require 'Client callable' checkbox: For GlideAjax to work, the Script Include must be marked as client callable.
6. Performance considerations: Questions may ask about best practices. Avoid synchronous GlideRecord calls in client scripts. Use GlideAggregate for counting instead of looping through records.
7. Common exam scenarios: • Which script type to use for form validation? (Client Script - onSubmit or Business Rule - Before) • How to make fields mandatory based on conditions? (UI Policy or Client Script - onChange) • How to update related records when a record changes? (Business Rule - After)
8. Watch for trick questions: Exam questions might present scenarios where a simple configuration (like UI Policy) would work instead of scripting. Always consider the simplest solution first.
10. Scope matters: Understand that scripts in scoped applications have different access than global scripts. ACLs and scope protection affect what scripts can access.