XML (Extensible Markup Language) is a versatile, text-based markup language designed to structure, store, and transport data in a format that is both human-readable and machine-readable. Unlike HTML, XML has no predefined tags, allowing users to define their own tags to describe data. It is widely used for data exchange between systems, application configuration, and in document formats like .docx and .xlsx.
Key Aspects of XML
- Purpose: Primarily used to carry and describe data, not to display it.
- Structure: Uses a hierarchical tree structure with opening and closing tags (e.g.,
<note><to>User</to></note>). - Flexibility: Users can create custom tags tailored to specific needs.
- Platform Independence: It is software- and hardware-independent, making it ideal for sharing data across different systems.
- Well-Formedness: XML documents must follow strict rules, such as having a single root element, proper nesting, and closing all tags.
Components of an XML Document
- Declaration: Defines the XML version and encoding (e.g.,
<?xml version="1.0" encoding="UTF-8"?>). - Tags and Elements: Used to structure data (e.g.,
<name>...</name>). - Attributes: Provide extra information about elements.
XML is foundational for many technologies, including RSS, MathML, and SVG. While often used for data interchange, it is considered more verbose and less efficient for storage compared to formats like JSON.