Listen to htmx:configRequest event to send parameters

This example shows how to listen to htmx:configRequest to pass parameters to all supported HTTP verbs (doc)

This event is triggered after htmx has collected parameters for inclusion in the request. It can be used to include or update the parameters that htmx will send

    document.addEventListener("htmx:configRequest", (evt) => {
        evt.detail.parameters["Name"] = "John Doe";
    });

On GET and DELETE, the parameters are accessible via Request.Query. For the rest, you can access the parameters via Request.Form.