For more Information refer below article:
- Microsoft ECM Team Blog: Configuring and Customizing the CQWP
- Heather Solomon: Customizing the CQWP and Custom Item Styles
- Brendon Schwartz: Connecting the CQWP without changing ItemStyle.xsl
- DDWRT Namespace Provides dozens of useful end-user functions such as IsPrivilegedUser() (for determining if working with an administrator), UserLookup() (for mapping usernames with data such as email addresses).
- We touched on the DDWRT namespace and URLEncode function in a previous blog post
There are also some good online tutorials:
Sample Example of XSLT in SharePoint Links: