Anliegen der Lagerbuchung einschränken

frappe.ui.form.on("Material Request", "validate", function(frm) {
    if(user=="user1@example.com" && frm.doc.purpose!="Material Receipt") {
        frappe.msgprint("You are only allowed Material Receipt");
        frappe.throw(__("Not allowed"));
    }
}

Next: Restrict User Based On Child Record