XPathExpression

This interface is a compiled XPath expression that can be evaluated on a document or specific node to return information from its DOM tree.

This is useful when an expression will be reused in an application, because it is just compiled once and all namespace prefixes which occur within the expression are preresolved.

Objects of this type are created by calling XPathEvaluator.createExpression().

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

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;