PEDI offers different options for validating XML documents, including the validation of a well-formed document. The structure of an XML document is formed by tags that begin with the character < and end with the character >. In an XML document, you can find start tags <example tag>, end tags </example tag>, or empty element tags <example tag/>, and these tags can be nested. An XML document is called well-formed when it follows the following set of rules:
They must contain at least one element.
They must contain a unique root element—this means a single opening and closing tag for the whole document.
The tags are case sensitive—this means that beginning and ending tags match (for instance,
<example Tag></example Tag>versus<example Tag></Example Tag>). The second tag set will throw an error.All of the tags must be nested properly, without overlapping.