<?xml version="1.0"?>
<note>
<to>Tove</to>
<from>Jani</from>
<heading>Reminder</heading>
<body>Don't forget me this weekend!</body>
</note>
The first line in the document: The XML declaration should always be included. It defines
the XML version of the document. In this case the document conforms to the 1.0 specification
of XML:
<?xml version="1.0"?>
The next line defines the first element of the document (the root element):
<note>
The next lines defines 4 child elements of the root (to, from, heading, and
body):
<to>Tove</to>
<from>Jani</from>
<heading>Reminder</heading>
<body>Don't forget me this weekend!</body>
The last line defines the end of the root element:
</note>
All XML elements must have a closing tag
In HTML some elements do not have to have a closing tag. The following code
is legal in HTML:
<p>This is a paragraph
<p>This is another paragraph
In XML all elements must have a closing tag like this:
<p>This is a paragraph</p>
<p>This is another paragraph</p>
XML tags are case sensitive
XML tags are case sensitive. The tag <Letter> is different from
the tag <letter>.
Opening and closing tags must therefore be written with the same case:
<Message>This is incorrect</message>
<message>This is correct</message>
All XML elements must be properly nested
In HTML some elements can be improperly nested within each other like this:
<b><i>This text is bold and italic</b></i>
In XML all elements must be properly nested within each other like this
<b><i>This text is bold and italic</i></b>
All XML documents must have a root tag
All XML documents must contain a single tag pair to define the root element.
All other elements must be nested within the root element. All elements can have
sub (children) elements. Sub elements must be in pairs and correctly nested
within their parent element:
XML elements can have attributes in name/value pairs just like in HTML. In
XML the attribute value must always be quoted. Study the two XML documents below.
The first one is incorrect, the second is correct:
<?xml version="1.0"?>
<note date=12/11/99>
<to>Tove</to>
<from>Jani</from>
<heading>Reminder</heading>
<body>Don't forget me this weekend!</body>
</note>
<?xml version="1.0"?>
<note date="12/11/99">
<to>Tove</to>
<from>Jani</from>
<heading>Reminder</heading>
<body>Don't forget me this weekend!</body>
</note>
