<!DOCTYPE html>
<html>
  <form>
    <input title="at least eight symbols containing at least one number, one lower, and one upper letter" type="text" pattern="(?=.*\d)(?=.*[a-z])(?=.*[A-Z]).{8,}" required />
    <input type="submit" value="Submit a strong password"/>
  </form>

  <form>
    <input type="text" title="email" required pattern="[^@]+@[^@]+\.[a-zA-Z]{2,6}" />
    <input type="submit" value="Submit an email"/>
  </form>

  <form>
    <input type="text" required pattern="(\+?\d[- .]*){7,13}" title="international, national or local phone number"/>
    <input type="submit" value="Submit an international, national or local phone number"/>
  </form>

  <form>
    <input type="email" required/>
    <input type="submit" value="Submit a W3C email"/>
  </form>
</html>

Created by Staffan Nöteberg, March 2012.