In computing, the term Extensible Stylesheet Language (XSL) is used to refer to a family of languages used to transform and render XML documents (e.g., XSL is used to determine how to display a XML document as a webpage^[1]).

Historically, the W3C XSL Working Group produced a draft specification under the name "XSL", which eventually split into three parts:

1. XSL Transformation (XSLT): an XML language for transforming XML documents
2. XSL Formatting Objects (XSL-FO): an XML language for specifying the visual formatting of an XML document
3. XML Path Language (XPath): a non-XML language used by XSLT, and also available for use in non-XSLT contexts, for addressing the parts of an XML document.

As a result, the term "XSL" is now used with a number of different meanings:

• Sometimes it refers to XSLT: this usage is best avoided. However, "xsl" is used both as the conventional namespace prefix for the XSLT namespace, and as the conventional filename suffix for files containing XSLT stylesheet modules
• Sometimes it refers to XSL-FO: this usage can be justified by the fact that the XSL-FO specification carries the title Extensible Stylesheet Language (XSL); however, the term XSL-FO is less likely to be misunderstood
• Sometimes it refers to both languages considered together, or to the working group that developed both languages
• Sometimes, especially in the Microsoft world, it refers to a now-obsolete variant of XSLT developed and shipped by Microsoft as part of MSXML before the W3C specification was finalized

XSL began as an attempt to bring the functionality of DSSSL, particularly in the area of print and high-end typesetting, to XML.

In response to a submission from Arbortext, Inso, and Microsoft,^[2] a W3C working group on XSL started operating in December 1997, with Sharon Adler and Steve Zilles as co-chairs, with James Clark acting as editor (and unofficially as chief designer), and Chris Lilley as the W3C staff contact. The group released a first public Working Draft on 18 August 1998. XSLT and XPath became W3C Recommendations on 16 November 1999 and XSL-FO reached Recommendation status on 15 October 2001.^[3]

• XSLT
• XSL Formatting Objects
• XPath

• "XSL language definition".
• "Extensible Stylesheet Language". Archived from the original on 2008-07-12. Retrieved 2003-11-28.
• Holman, G. Ken (2002-03-20). "What is XSL-FO". XML.com. O'Reilly Media, Inc. Retrieved 2008-09-01.

• tutorial and reference of XSLT and XSL-FO
• XML Focus Topics: CSS, XSL, XSL-FO Archived 2008-05-12 at the Wayback Machine
• IBM XSL Formatting Objects Composer Archived 2011-07-17 at the Wayback Machine