Section 2: Well-Formed XML Documents

In this section, we'll delve into the concept of well-formed XML documents, exploring the criteria that define their structure. Additionally, we'll cover the usage of entity references to handle special characters.

Well-Formed XML Criteria

Understanding the Concept of Well-Formed XML

A well-formed XML document adheres to specific syntactic rules, ensuring its structure is valid and can be processed correctly. Key criteria include:

• Proper Nesting: Elements must be properly nested, and each opening tag must have a corresponding closing tag.

• Case Sensitivity: XML is case-sensitive; therefore, tags and attribute names must be consistent in their casing.

• Root Element: The document must have a single root element that contains all other elements.

Example of a Well-Formed XML Document:

<library>

    <book>

        <title>Well-Formed XML Guide</title>

        <author>Chris Johnson</author>

    </book>

</library>

Common Mistakes and How to Avoid Them

Avoiding common mistakes is crucial to maintaining the well-formed nature of XML documents. Examples of mistakes include unmatched tags, improper nesting, and missing attributes.

• Entity References

• Using Entity References for Special Characters

In XML, certain characters have special meanings and cannot be used directly. Instead, we use entity references to represent them.

• &lt;: Represents the less-than symbol <.

• &gt;: Represents the greater-than symbol >.

• &amp;: Represents the ampersand &.

• &quot;: Represents the double quotation mark ".

• &apos;: Represents the apostrophe '.

Example:

<description>

    This tag contains &lt; and &gt; symbols.

</description>

Entity references ensure that special characters do not interfere with the XML structure.

Stay tuned for upcoming lessons where we'll explore more advanced XML concepts and practices!