How to get name of doc from webform

Frappe Framework Customization
1 
	// bind events here
	$('button[type="submit"]').click(function(frm){
		var x = $('input[type="file"]');
		var new_parents="Home/"+frm.doc.name;
		frappe.call({
				method: "frappe.core.doctype.file.file.move_file",
				args: {
					"file_list": x,
					"new_parent": new_parents,
					"old_parent": "Home/Attachment"
				},
				callback: function(r) {
					if(r.message) {
						console.log(r.message);
					}
				}
			})
	})
})```


when i try to run above code i get error in console
```Uncaught TypeError: Cannot read property 'name' of undefined(…)````

```var new_parents="Home/"+frm.doc.name;```

error is at here