Check & Validate XML Syntax Online Validate XML syntax with error detection for malformed tags, missing closings, and encoding issues.

The tool works by utilizing the DOMParser API to parse the input string as an XML document. This process involves creating a new instance of the DOMParser object and calling its parseFromString method with the input string and the 'application/xml' MIME type. The resulting Document object is then checked for parser errors by querying for elements with the tag name 'parsererror'. If such an element is found, it indicates that the XML is malformed, and the tool extracts the error message from the element's text content.

To analyze the XML document structure, the tool uses various DOM methods and properties, including getElementsByTagName to retrieve a collection of all elements in the document, and attributes to access the attributes of the root element. It also employs JavaScript data structures such as arrays and sets to store information about the unique tag names and attribute values. The tool's ability to extract XML declaration details relies on string manipulation techniques, specifically regular expressions, to match version and encoding information.

The validation result is presented in a detailed report that includes success messages marked with ✓ and error messages marked with ✗, allowing users to easily identify and fix issues in their XML code. This report is generated by iterating over an array of detail messages, which are constructed based on the parsing outcome and the analysis of the XML document structure. The tool's user interface is built using React components, including useState and useCallback hooks to manage state and handle events. The input string is stored in a state variable and updated whenever the user types in the textarea element.

In terms of file formats, the tool only supports XML 1.0 documents, as specified by the W3C standard. It does not support other XML variants or related formats like XHTML or JSON. The tool's validation logic is based on the DOMParser API's built-in support for parsing XML documents, which ensures compliance with the W3C standard. By using this API and following established best practices for working with XML data, the tool provides a reliable and efficient way to validate XML documents in a web-based environment.