Client Script

Purpose

  • Control form behavior (UX)
  • React to user interaction
  • Provide immediate feedback before submit

Client Scripts exist to improve the user experience — not to enforce data integrity.

Runs

  • Client
  • Trigger types:
  • onLoad – when the form loads
  • onChange – when a field value changes
  • onSubmit – right before submit
  • onCellEdit -

Client Scripts do not run for:

  • imports
  • integrations
  • background scripts
  • updates outside the UI

Client Scripts Execute

Use When

  • Show / hide fields
  • Make fields mandatory or read-only
  • Client-side validation
  • Default values for new records
  • Field-to-field interactions

Do NOT use when:

  • Data integrity is critical
  • Logic must always run
  • Updating records in the database
  • Cross-table enforcement

If it must always happen → Business Rule

Touches

  • Tables: current form table only
  • Fields: via g_form
  • APIs:
  • g_form.getValue()
  • g_form.setValue()
  • g_form.setMandatory()
  • g_form.setVisible()
  • g_form.setReadOnly()
  • g_form.showFieldMsg()

g_form is the primary API for Client Scripts

Types of Client Scripts

onLoad

  • Runs when the form loads
  • Best for:
  • initial visibility
  • default values
  • read-only setup

Note: Runs every time the form opens (new + existing records)

onChange

  • Runs when a field value changes
  • Most commonly used
  • Best for:
  • dynamic validation
  • reacting to user input

Note: Can run frequently — keep logic light

onSubmit

  • Runs right before submit
  • Best for:
  • final validation
  • blocking submission

Note: Must return true or false

onCellEdit

Common Mistakes

  • Trying to update the database
  • Putting server logic in client scripts
  • Forgetting users can bypass the UI
  • Overusing onChange scripts
  • Duplicating logic that belongs in Business Rules

Performance & Safety Rules

  • Keep scripts small and focused
  • Avoid loops in onChange
  • GlideRecord is not available
  • Never trust client data alone
  • Pair with Business Rules for critical logic

1-Min Example

Requirement: If priority = 1 → justification is mandatory

Where: onChange Client Script on priority

Logic:

  • If priority == 1 → make justification mandatory
  • Else → remove mandatory

Relationship to UI Policies

  • UI Policies should be attempted first
  • Client Scripts used when:
  • logic is conditional
  • calculations are needed
  • UI Policies are too limited

Rule of thumb: UI Policy → Client Script → Business Rule

Mental Shortcut

Client Script = UX logic Business Rule = truth enforcement

Mental Shortcut

UI Policy = simple UI rules Client Script = advanced UI logic