XPathEvaluator: createExpression() method

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

This method compiles an XPathExpression which can then be used for (repeated) evaluations of the XPath expression.

Syntax

createExpression(expression)
createExpression(expression, resolver)

Parameters

expression: A string representing the XPath expression to be created.
resolver Optional: A Node, null, or any object implementing the lookupNamespaceURI method. Permits translation of all prefixes, including the xml namespace prefix, within the XPath expression into appropriate namespace URIs.

Return value

A XPathExpression representing the compiled form of the XPath expression.

Exceptions

INVALID_EXPRESSION_ERR

If the expression is not legal according to the rules of the XPathEvaluator, an XPathException of type INVALID_EXPRESSION_ERR is raised.

NAMESPACE_ERR

If the expression contains namespace prefixes which cannot be resolved by the specified XPathNSResolver, a DOMException of type NAMESPACE_ERROR is raised.

Examples

The following example shows the use of the evaluate() method.

HTML

html

<div>XPath example</div>
<div>Number of &lt;div&gt;s: <output></output></div>

JavaScript

const xpath = "//div";
const evaluator = new XPathEvaluator();
const expression = evaluator.createExpression(xpath);
const result = expression.evaluate(
  document,
  XPathResult.ORDERED_NODE_SNAPSHOT_TYPE,
);
document.querySelector("output").textContent = result.snapshotLength;

Result

Specifications

Specification
DOM Standard # dom-xpathevaluatorbase-createexpression

Browser compatibility

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