Make a field read-only in a Client Script

The g_form.setReadOnly() method provides client-side field protection that's visually obvious to users but fundamentally incomplete for data integrity. Unlike server-side enforcement, this creates a UX convenience layer that can be bypassed by anyone who understands how to manipulate form submissions. The most common mistake developers make is treating this as actual security — it's presentation logic that must be backed by Data Policies or Business Rules to prevent circumvention through direct API calls, mobile apps, or browser developer tools.

When to use this

• Preventing accidental edits to calculated or system-managed fields like total_cost or approval_history
• Conditional field locking based on user roles or record state where the business logic allows exceptions
• Workflow-based form states where fields should be locked during specific approval stages
• Creating dependent field relationships where one field controls the editability of another

When NOT to use this

• Enforcing security policies or compliance requirements — use ACLs and Data Policies instead
• Fields that should never be editable after record creation — use read_only=true dictionary attribute
• Mobile or Service Portal forms where client scripts don't execute — use UI Policies instead
• Performance-critical forms with many conditional fields — UI Policies are more efficient

Key behaviors and gotchas

• Client-side enforcement only — values can still be modified through REST API, Import Sets, or Business Rules
• Read-only fields are excluded from form submission payload, so server-side scripts won't see attempted changes
• Reference fields made read-only will disable both the lookup icon and autocomplete functionality
• Choice fields become unclickable dropdowns but retain their visual styling unlike disabled fields
• Always check isLoading and isTemplate in onChange to prevent conflicts with form initialization
• Setting setReadOnly(field, false) won't override dictionary-level read-only attributes or ACL restrictions