R package htmltidy. Tidy Up and Test XPath Queries on HTML and XML Content. HTML documents can be beautiful and pristine. They can also be wretched, evil, malformed demon-spawn. Now, you can tidy up that HTML and XHTML before processing it with your favorite angle-bracket crunching tools, going beyond the limited tidying that ’libxml2’ affords in the ’XML’ and ’xml2’ packages and taming even the ugliest HTML code generated by the likes of Google Docs and Microsoft Word. It’s also possible to use the functions provided to format or ”pretty print” HTML content as it is being tidied. Utilities are also included that make it possible to view formatted and ”pretty printed” HTML/XML content from HTML/XML document objects, nodes, node sets and plain character HTML/XML using ’vkbeautify’ (by Vadim Kiryukhin) and ’highlight.js’ (by Ivan Sagalaev). Also (optionally) enables filtering of nodes via XPath or viewing an HTML/XML document in ”tree” view using ’xml-viewer’ (by Julian Gruber). See <https://github.com/vkiryukhin/vkBeautify> and <https://github.com/juliangruber/xml-viewer> for more information about ’vkbeautify’ and ’xml-viewer’, respectively.