code: func SetCORS(w http.ResponseWriter, o *regexp.Regexp, r *http.Request) {
  	origin := r.Header.Get("Origin")
  	if origin == "" {
  		return
  	}
  
  	for k, v := range corsHeaders {
  		w.Header().Set(k, v)
  	}
  
  	if o.String() == "^(?:.*)$" {
  		w.Header().Set("Access-Control-Allow-Origin", "*")
  		return
  	}
  
  	if o.MatchString(origin) {
  		w.Header().Set("Access-Control-Allow-Origin", origin)
  	}
  }
docs: // Enables cross-site script calls.