Get selected row data from Child Table

I created a custom child button in one of my child table. Now I want to get selected row’s specific data on that custom button click.

This child table. I want to get row’s all data on that Hello button click. I’ve used
let selected = frm.get_selected()

But cannot understand how to get all fields data.

@Cross_X you already got the names of selected rows . you can the data with many ways . for example use (locals[cdt][cdn])
or you can get the object from the database using (frappe.get_doc(cdt, cdn); )
where // cdt is Child DocType name i.e Quotation Item
// cdn is the row name for e.g bbfcb8da6a

How to use (locals[cdt][cdn]) in let selected = frm.get_selected()?

first store the selected rows in the variable selected ,exactly the way you did it .
then fetch the data from the array and for each name get the object

let selected = frm.get_selected()
selected.child_table_name.forEach(function(item, index, array) {
let row = locals["Child Doctype Type",item]