I want to make entire child table read only for certain users

How to make a entire child table read only for particular users?
Is there any solutions.

Possible using the client script.

How is it possible?

Please check the syntax and apply it according to the scenario.

frappe.ui.form.on("Your DocType", {
    refresh: function(frm) {
        if (frm.session.user == "user1@testmail.com") {
            frm.set_df_property('your_table_name', 'read_only', true);
        }
    }
});

can we make certain field read only for certain users in child table?

Please check the reference: