Remove jQuery from working examples

[fstrr]

These working examples use jQuery. It would be nice to remove that and use regular JavaScript:

1. Using aria-alertdialog to Identify Errors
2. Using ARIA live regions or role=alert to identify errors (the technique for this also needs updating as it references the jQuery)
3. Input Error Notification with aria-live=assertive and aria-invalid using jQuery (from ARIA 21, which also needs updating to remove the references to jQuery)
4. Forms: Using aria-invalid