recipe: cs, 02

Author: NagariaHussain

src/assets/images/cookbook/client-scripts/district_doctype.png

@@ -0,0 +1,36 @@
+---
+title: Filtering Link Fields
+description: Using the `set_query` and `get_query` API to filter your link fields.
+---
+
+## Use Case
+
+In India, there are states and each state has several districts. Suppose, we want to implement a **Location** form for India which asks the user to select a **State** and then a **District**. But we have to make sure the District field only shows districts belonging to the selected state:
+
+![Screenshot showing filter getting applied](../../../../assets/images/cookbook/client-scripts/filtered_district_field.png)
+
+The district doctype has a field which stores which State it belongs to:
+
+![District DocType Form View](../../../../assets/images/cookbook/client-scripts/district_doctype.png)
+
+## The Script
+
+```js {3-9}
+frappe.ui.form.on('Location', {
+ refresh(frm) {
+     frm.set_query("district", (doc) => {
+         return {
+             filters: {
+                 "state": doc.state // whatever state is selected
+             }
+         }
+     });
+ }
+})
+```
+
+The JS API that let's you apply filters to link fields is highlighted above. As you can see above, `doc` (in this case, the **Location** document) is provided for you. Here, `doc` is equivalent to `frm.doc`.
+
+## Learn More
+
+You can read more about `set_query` API [here](https://frappeframework.com/docs/user/en/guides/app-development/overriding-link-query-by-custom-script).