XSL: Extensible Stylesheet Language
XSL is a powerful language that can take the contents of PCF files (the files that exist on the staging server, also known as Publish Control Files) and format them into dynamic web pages. The files inside the XSL folder are crucial to the functionality of page preview and publish.
Every time a page is previewed or published, XSL is being used to transform the contents of the PCF file into an actual web page. Any particular PCF file can be connected to one or more XSL files, and any XSL file can be connected to one or more other XSL files.
How do XSL files make webpages out of PCF files?
PCF files are not complete webpages. These files only contain the content that is available to users edit. For example, a PCF file for an interior page only contains three content areas: main content, right content, and far right content. It also contains information such as Page Title and Number of Columns that can be modified using Page Properties.
When a user is previewing or publishing a PCF file (in this case, an interior page), XSL goes through the information in the PCF file and transforms it into a webpage. It puts the content areas in the correct spot, adds the header and footer, and includes the correct navigation file for the section the page exists in.
How do XSL files work together?
Each XSL file has a different job to make the transformation process (and the finished product) most efficient. Although a PCF file might only directly reference one XSL file (such as "interior.xsl" or "landing.xsl"), often times that XSL will import other XSL files ("common.xsl").
In this example, interior.xsl first formats the content unique to that PCF file, but common.xsl adds all of the other information that is "common" to all other page types, such as the header and footer, and information about what to do with special items such as news feeds and galleries. Additionally, common.xsl may even import even more XSL files that have very specific jobs, such as formatting special items.