XML

eXtensible Markup Language (XML) is a format that has been widely adopted to exchange information between companies, documents, and programs. It has a notation similar to HTML, using tags. As a matter of fact, HTML is a special case of XML. With HTML, tags have meanings and are meant to be interpreted by a browser. In XML, tags can mean anything or nothing at all, but the rules are stricter. Of course, if you are the creator of the XML file, we hope that the tags have some meaning to you.

You, as a web developer, may never use XML, but it is important that you know that it exists. It has been created to be a data format that is both machine readable and human readable. Humans will be able to read the content that is inside, as XML files are basically text files; computer programs can read them because they are well structured. There are several areas where the XML format is applied. We only mention a few of them here: