Have you noticed small purple numbers and letters at end of paragraphs in some sites like Doug Engelbart’s Bootstrap Institute web site.
Purple is a small suite of tools designed to create HTML documents with “purple” numbers. These purple numbers are HTML anchors attached to every paragraph in a document, which allow you to link to these paragraphs. Purple does this by automatically creating name anchors with static and hierarchical addresses at the beginning of each text node, and by displaying these addresses as links at the end of each text node.
How Purple works? “Purple consists of an XML DTD, an XSLT script for transforming the XML into HTML, various Perl scripts for preprocessing the XML, and a CGI script for displaying different versions of an HTML file.” Figure that out!
There is a Case Study about Adding Purple Numbers to Web Sites which describes personal experiences adding purple numbers with basic problems and the tools and processes and analyze the strengths and weaknesses.
So next time you see these purple numbers on websites, you would not be baffled like I was. Or maybe you could add them to your site too and amuse your visitors.