This post goes over how to evaluate an XPath expression with JavaScript in the DOM.

document.evaluate

Use document.evaluate to evaluate an XPath expression <MY_XPATH> in the DOM:

document.evaluate('<MY_XPATH>', document, null, XPathResult.ANY_TYPE, null);

For example, to get all buttons containing the text Yes in the document.body:

const result = document.evaluate(
  '//button[contains(text(), "Yes")]',
  document.body,
  null,
  XPathResult.ANY_TYPE,
  null
);

let button;
const buttons = [];

while ((button = result.iterateNext())) {
  buttons.push(button);
}

console.log(buttons);

Here’s a helper function that evaluates XPath:

/**
 * Evaluate XPath expression.
 *
 * @param {string} xpathExpression - XPath expression.
 * @param {HTMLElement} [contextNode=document] - Context node for the query.
 * @returns {HTMLElement[]}
 */
function evaluateXPath(xpathExpression, contextNode = document) {
  const result = document.evaluate(
    xpathExpression,
    contextNode,
    null,
    XPathResult.ANY_TYPE,
    null
  );

  let element;
  const elements = [];

  while ((element = result.iterateNext())) {
    elements.push(element);
  }

  return elements;
}

Gist

Miscellaneous

Check out XPath cheatsheet.