Allow CORS: Access-Control-Allow-Origin is a free Chrome add-on developed by Muyor. This add-on allows users to easily add the (Access-Control-Allow-Origin: *) rule to the response header, enabling cross-domain Ajax requests in web applications.

With Allow CORS: Access-Control-Allow-Origin, users can simply activate the add-on and perform their desired request. By default, modern browsers block Cross-Origin Resource Sharing (CORS) in JavaScript APIs. However, installing this add-on will unblock this feature, providing users with the ability to make cross-domain requests.

Upon installation, the add-on is inactive by default, indicated by a grey "C" letter in the toolbar icon. To activate the add-on, users can open the toolbar popup and press the toggle button on the left side. Once activated, the toolbar icon will turn orange, indicating that the add-on is active.