## Example to fetch value in a child table field from master doctype


### Sample Script to fetch expiry_date field from Batch doctype to Sales Invoice Item table

Step 1: Create Custom Script for _**Sales Invoice**_ (parent) doctype

Step 2: Script as below & Save

```
frappe.ui.form.on("Sales Invoice Item", "batch_no", function(frm, cdt, cdn) {
	var d = locals[cdt][cdn];
    	frappe.db.get_value("Batch", {"name": d.batch_no}, "expiry_date", function(value) {
    		d.expiry_date = value.expiry_date;
    	});
});
```