In HTML form, there is a field named "website". If a person enters "www.wikipedia.org", then the AJAX library can verify that the site "www.wikipedia.org" is listed in Google. If the person enters "www.gsdjklgjsdklgjklj.com", then the Ajax library can verify that this site is not listed in Google.
A few requirements:
* There should be a simple animated GIF appearing whenever the AJAX call is in progress.
* It must not hang or freeze the browser.
* It must work in IE and Firefox.
* A sample should be provided to demonstrate how this code can be used to prevent a HTML form from submitting before the field is valid.