<?xml version="1.0"?>
<!-- Copyright w3school.com.cn -->
<!DOCTYPE note [
  <!ELEMENT note    (to,from,heading,body)>
  <!ELEMENT to      (#PCDATA)>
  <!ELEMENT from    (#PCDATA)>
  <!ELEMENT heading (#PCDATA)>
  <!ELEMENT body    (#PCDATA)>
]>
<note>
<to>George</to>
<fromm>John</fromm>
<heading>Reminder</heading>
<body>Don't forget the meeting!</body>
<ps>I love you</ps>
</note> 