Parts of an XML Document

An XML document looks like this:

<?xml version="1.0" encoding="utf-8" ?>
<!DOCTYPE bookinfo "bookinfo.dtd">
<?cursor line="122" col="48" ?>
<!-- This is a comment -->
<bookinfo id="48">
<title>Moby Duck&mdash;The Great White Mallard</title>
</bookinfo>

Basically it consists of plain text with embedded markup. Markup directives are set off from the main text using enclosing <> characters.

An XML document can contain the following components:

The XML declaration:
```
<?xml version="1.0" encoding="utf-8" ?>
```
This provides basic information about the XML document such as the XML version it uses or its character encoding scheme.
A document type declaration:
```
<!DOCTYPE bookinfo "bookinfo.dtd">
```
This defines an optional DTD (document type definition—information about the structure of the document).
A processing instruction:
```
<?cursor line="122" col="48" ?>
```
An XML document may contain processing instructions. These are not considered to be part of the document; instead they are special markers that can be used by XML tools (such as an XML editor).
A comment:
```

```
Comments are ignored during XML processing.
An element:
```
<bookinfo>
```
The top-level element is called the root element.
All elements must have a corresponding closing tag:
```
</bookinfo>
```
An attribute:
```
<bookinfo id="48">
```
An element may contain zero or more attributes. Attributes specify additional information about an element.
An entity:
```
&mdash;
```
An entity is the XML version of a macro: when a document is processed, entities are replaced with a corresponding set of characters.
Text:
```
Moby Duck
```
This is actual, textual content of the document.