using web services once it became easy to retrieve documents and parse documents over http using programsit did not take long to develop an approach where we started producing documents that were specifically designed to be consumed by other programs ( not html to be displayed in browserthere are two common formats that we use when exchanging data across the web extensible markup language (xmlhas been in use for very long time and is best suited for exchanging document-style data when programs just want to exchange dictionarieslistsor other internal information with each otherthey use javascript object notation (json(see www json orgwe will look at both formats extensible markup language xml xml looks very similar to htmlbut xml is more structured than html here is sample of an xml documentchuck + each pair of opening ( and closing tags ( represents element or node with the same name as the tag ( personeach element can have some textsome attributes ( hide)and other nested elements if an xml element is empty ( has no content)then it may be depicted by self-closing tag ( often it is helpful to think of an xml document as tree structure where there is top element (hereperson)and other tags ( phoneare drawn as children of their parent elements