Mismatched Tags in XML
XML is case-sensitive, meaning <Item> and <item> are two completely different tags. A mismatched tag error occurs when the closing tag name does not exactly match the opening tag name, including case. This also happens when tags are closed in the wrong order (improper nesting).
Why It Matters
The XML parser rejects the document immediately. This is a common source of bugs when developers accustomed to case-insensitive HTML start writing XML, or when copying content between documents with different naming conventions.
Code Examples
<?xml version="1.0" encoding="UTF-8"?>
<Catalog>
<Item>
<Name>Widget</name>
<Price>9.99</price>
</item>
</catalog><?xml version="1.0" encoding="UTF-8"?>
<Catalog>
<Item>
<Name>Widget</Name>
<Price>9.99</Price>
</Item>
</Catalog>How to Fix
- 1Ensure every closing tag matches the exact case of its opening tag: <Name>...</Name>, not <Name>...</name>.
- 2Adopt a consistent naming convention (camelCase, PascalCase, or lowercase) and stick to it throughout the document.
- 3Check that tags are nested correctly. Close inner tags before outer tags.
- 4Use an XML-aware editor with syntax highlighting to spot case mismatches quickly.
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