urlStr top-level property
A regular expression pattern that matches basic URL formats.
This pattern matches optional http:// or https:// protocols, followed by
a domain name, optional subdomains, and optional path segments.
Examples of valid formats:
Implementation
String urlStr =
r'^(https?:\/\/)?([\da-z\.-]+)\.([a-z\.]{2,6})([\/\w \.-]*)*\/?$';