XSL Language

• Whereas the ".xml" file contains the data, the ".xsl" file is the "source code" containing the computer instructions that are read by the XML parser engine inside web browsers and other computer applications. It is the XML parser engine that manipulates and transforms the xml data into the output format. This transformation is carried out using powerful search, match and translate functions within the XPath and XQuery language subsets in XSL, as well as programming operators and functions within XSL itself.
  
  There are two kinds of XSL: XSLT and XSL-FO.
  
  

XSLT

• XSLT or "XSL transformations" refers to data output to another text file, such as XML in a different format for a different computer application, or to an HTML, TXT or CSV file.
  
  

XSL-FO

• XSL-FO, or "XSL-Formatting Objects," refers to data output to a binary file, such as to PDF, Word or Excel. In this case, special software known as the formatting objects processor needs to be installed in order to generate and populate the binary file from the xml data.