// Generate response header "Link: ; rel=preconnect" // HREF is provided by the request header X-Link function handleRequest(request, response) { response.setHeader("Cache-Control", "no-cache", false); response.setHeader( "Link", "<" + request.queryString + ">; rel=preconnect" + ", " + "<" + request.queryString + ">; rel=preconnect; crossOrigin=anonymous" ); response.write("check that header"); }