Changes in Grand Total does not reflact in Purchase Invoice

ERPNext
1

There is my code

frappe.ui.form.on("Purchase Invoice","refresh", function(frm, doctype, name) {
	cur_frm.doc.grand_total = 10000; // some value based on some calculation
	cur_frm.refresh_field('grand_total');
});

Here I am trying to change ‘grand total’ value based on some calculation in ‘refresh’ but it is not changed. Can anybody explain, why this is happening?

2

You should do the calculation part when the field which is used to calculate the grand total is changed.

frappe.ui.form.on("Purchase Invoice", "some_fieldname", function(frm, doctype, name) {
    frm.set_value('grand_total', calculated_value);
});
3

Thanks… I got your point, but my doubt is that why it is not changed in ‘refresh’ or ‘onload’