XPath Tester

Evaluates an XPath expression against an XML document entirely in the browser using DOMParser and Document.evaluate. It parses your XML (rejecting malformed input with a parse error), runs the expression, and renders the typed result — strings, numbers, booleans, or serialized node sets — with a match count and per-result type label. Four quick-fill example expressions and a starter XML document ship with the tool.

1. Paste your XML into the XML Input card (a three-`<child>` sample document is preloaded). 2. Type an XPath expression into the XPath Expression field, or click one of the four example chips (`//element`, `//element/@attr`, `count(//element)`, `/root/child/text()`) to fill it. 3. Click Execute (or press Enter in the expression field) to evaluate. 4. Read the Results card: it shows the match count ("N matches") and each result with a type label — `Result (string|number|boolean)` for scalar expressions, or `Node 1`, `Node 2`, ... for node-set expressions serialized back to XML. 5. Any parse error (invalid XML) or evaluation error (invalid XPath) appears in a red banner above the results.

The tool calls `doc.evaluate(xpath, doc, null, XPathResult.ANY_TYPE, null)` and dispatches on `resultType`: - STRING_TYPE → one result labeled `Result (string)`. - NUMBER_TYPE → one result labeled `Result (number)`, value coerced to string (this is what `count(//child)` returns). - BOOLEAN_TYPE → one result labeled `Result (boolean)` (e.g. `count(//child) > 0`). - ORDERED_NODE_SNAPSHOT_TYPE / UNORDERED_NODE_SNAPSHOT_TYPE → multiple results, each serialized via XMLSerializer and labeled `Node 1`, `Node 2`, etc. - FIRST_ORDERED_NODE_TYPE → a single node result (or empty string if no node matched). XML is parsed in `application/xml` mode, so HTML-style void tags, unquoted attributes, or entity issues will surface as a parsererror element and be shown as `Invalid XML: ...`. The default `application/xml` mode also means HTML documents are not parsed correctly — feed well-formed XML only.