What is the jQuery Validation plugin's default behavior for onkeyup?

What is the jQuery Validation plugin's default behavior for onkeyup?

On the documentation page, it says about the "onkeyup" option:
 Validate elements on keyup. As long as the field is not marked as invalid, nothing happens. Otherwise, all rules are checked on each key up event.
However, in my experience with version 1.10.0, validation fires on the element on keyup even before the field has been marked invalid.  This results in the premature display of validation error messages.  That can't be right... right?

Here's some code to demonstrate the issue.  Try entering a number that starts with a decimal point, or any email address, and you'll see how the invalid messages display too soon:

  2. <!DOCTYPE html>
  3. <html>
  4. <head>
  5. <title>Experiment</title>
  6. <script src="//ajax.aspnetcdn.com/ajax/jQuery/jquery-1.8.0.js"></script>
  7. <script src="//ajax.aspnetcdn.com/ajax/jquery.validate/1.10.0/jquery.validate.js"></script>
  8. </head>
  9. <body>
  10. <form>
  11. <fieldset>
  12. <div>
  13. <label for="number">Number:</label>
  14. <input type="text" name="number" class="number" />
  15. </div>
  16. <div>
  17. <label for="email">Email:</label>
  18. <input type="text" name="email" class="email" />
  19. </div>
  20. </fieldset>
  21. <div>
  22. <input type="submit" />
  23. </div>
  24. </form>
  25. <script>
  26. $("form").validate();
  27. </script>
  28. </body>
  29. </html>