XSLT (Extensible Stylesheet Language Transformations) is a language for transforming XML documents into other XML documents, or other objects such as HTML for web pages, plain text or into XSL Formatting Objects which can then be converted to PDF, PostScript and PNG.
Typically, input documents are XML files, but anything from which the processor can build an XQuery and XPath Data Model can be used, for example relational database tables, or geographical information systems.
The original document is not changed; rather, a new document is created based on the content of an existing one.
XSLT is a Turing-complete language, meaning it can perform any calculation that can be performed by a modern computer program.
Read more about XSLT: History, Processor Implementations, XSLT and Streaming, XSLT and XPath, XSLT and XQuery Compared, XSLT Media Types, XSLT Examples