By tagging these information elements according to their meaning, rather than how they look in one particular document, external processes can be used to act on these information objects, making maximum use of them. In order to create these languages, you will need to understand the information you are defining. There are two forms of XML, valid XML and well-formed XML . Just click the link in the left menu bar. XML A well-formed XML document contains start tags , end tags , and content .
Content is everything between the start tag and the end tag.
While element names are generally nouns, attributes are more likely to be adjectives. That is, elements describe the thing, while attributes provide further information about the thing. For example, suppose you want to send a purchase order to a supplier, but you wanted to put a time limit on when the vendor supplied the goods. Notice that the attribute value is quoted. A well-formed XML document must have a single root element that contains the rest of the document.