XML (Extensible Markup Language) is a versatile, text-based markup language used to store and transport data. Unlike HTML, which focuses on how data looks (presentation), XML focuses on what the data is (meaning).
Think of XML as a way to create a digital filing system where you get to name your own folders and labels.
Extensible: You can create your own tags (e.g., <price>, <model>, <author>). There are no predefined tags like in HTML.
Self-Descriptive: The tags describe the data they contain, making the file easy for both humans and machines to read.
W3C Standard: It is an open standard maintained by the World Wide Web Consortium, ensuring it works across all platforms and software.
An XML document is a tree structure that starts with a Root element and branches out into Child elements.
XML
<?xml version="1.0" encoding="UTF-8"?>
<bookstore> <book category="fiction"> <title>The Great Gatsby</title> <author>F. Scott Fitzgerald</author>
<year>1925</year>
<price>12.99</price>
</book>
</bookstore>
While JSON has become more popular for simple web APIs, XML remains the "heavyweight" champion in several sectors:
Office Documents: Files like .docx, .xlsx, and .pptx are actually zipped XML files.
Configuration: Many enterprise applications (like those in Java or .NET) use XML for complex system settings.
Industry Standards: Formats like RSS feeds, SVG images, and SOAP (web services) are built entirely on XML.
Data Exchange: Essential in banking, healthcare, and government systems where data validation and strict structure are critical.
This file acts as the "container" for your inputs and the calculated result.
<?xml version="1.0" encoding="UTF-8"?>
<CalculationTask>
<Inputs>
<Number1>15</Number1>
<Number2>10</Number2>
</Inputs>
<Result>
<Value>150</Value>
<Status>Calculated</Status>
<Destinations>
<Target>Screen</Target>
<Target>Printer</Target>
</Destinations>
</Result>
</CalculationTask>
If you want to stay strictly within the XML family, you can use XSLT (Extensible Stylesheet Language Transformations). XSLT can take your XML data and "transform" it into a format the screen or printer understands (like HTML or PDF).
Example XSLT Logic snippet:
XML
<xsl:template match="/">
<html>
<body>
<h2>Calculation Result</h2>
<p>The product is:
<xsl:value-of select="CalculationTask/Inputs/Number1 * CalculationTask/Inputs/Number2"/>
</p>
</body>
</html>
</xsl:template>