# Chained Select

Chained Select is a Pro field for hierarchical choices such as Country →
Region → City. Add it from the Advanced Fields palette, then edit **Chained
levels (JSON)** in the field settings.

Each level is an object with a `label` and an `options` array. Every option has
`value` and `label`; options after the first level also use `parent` to identify
the value that enables them:

```json
[
  {"label":"Country","options":[{"value":"us","label":"United States"}]},
  {"label":"State","options":[{"value":"ny","label":"New York","parent":"us"}]}
]
```

The browser progressively enables and filters each select. The submission
handler independently checks every selected value against the saved hierarchy,
including the parent relationship, so hidden or forged child values are
rejected server-side.