The XML Validator Online BETA is using the following components:

jQuery 1.3.2(
jQuery Form Plugin(
dp.SyntaxHighlighter 1.4.1(
XPath for jQuery(
Konami Command(

Thanks Ajaxload( for the good ajax-loading.gif generator.
Thanks Iconfinder( for the convenient icon search interface.

Thanks Khodjaev Stanislav( for error.png.
Thanks Everaldo( for fatal.png and success.png.
Thanks Liam McKay( for warning.png.