XML Syntax

The syntax rules of XML are very simple and logical. The rules are easy to learn, and easy to use.

XML documents must contain one root element that is the parent of all other elements:

In this example is the root element:

This line is called the XML prolog:

The XML prolog is optional. If it exists, it must come first in the document.

XML documents can contain international characters, like Norwegian 酶忙氓 or French 锚猫茅.

To avoid errors, you should specify the encoding used, or save your XML files as UTF-8.

UTF-8 is the default character encoding for XML documents.

Character encoding can be studied in our Character Set Tutorial.

UTF-8 is also the default encoding for HTML5, CSS, JavaScript, PHP, and SQL.

In XML, it is illegal to omit the closing tag. All elements must have a closing tag:

This is a paragraph.

Note: The XML prolog does not have a closing tag! This is not an error. The prolog is not a part of the XML document.

XML tags are case sensitive. The tag is different from the tag .

Opening and closing tags must be written with the same case:

"Opening and closing tags" are often referred to as "Start and end tags". Use whatever you prefer. It is exactly the same thing.

In HTML, you might see improperly nested elements:

In XML, all elements must be properly nested within each other:

In the example above, "Properly nested" simply means that since the element is opened inside the element, it must be closed inside the element.