The Web was originally created to serve HTML documents. Now it is used to serve all sorts of documents as well as data of different kinds. Nevertheless, HTML is still the main document type delivered over the Web.
HTML has been through a large number of versions, with the current version being HTML5. There have also been many “vendor” versions of HTML, introducing tags that never made it into the standards.
HTML is simple enough to be edited by hand. Consequently, many HTML documents are “ill formed,” which means they ...
