code: func IsURL(str string) bool {
  	if str == "" || len(str) >= 2083 || len(str) <= 3 || strings.HasPrefix(str, ".") {
  		return false
  	}
  	u, err := url.Parse(str)
  	if err != nil {
  		return false
  	}
  	if strings.HasPrefix(u.Host, ".") {
  		return false
  	}
  	if u.Host == "" && (u.Path != "" && !strings.Contains(u.Path, ".")) {
  		return false
  	}
  	return rxURL.MatchString(str)
  
  }
docs: // IsURL check if the string is an URL.