Firefox Tomorrow

web api instance method

Document: createExpression() method

View on MDN ↗

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

You must call this method on the same document that you run the expression against.

Syntax

createExpression(xpathText, namespaceURLMapper)

Parameters

  • xpathText
    • : A string which is the XPath expression to be compiled.
  • namespaceURLMapper
    • : A function which maps a namespace prefix to a namespace URL (or null if none needed).

Return value

XPathExpression

Examples

const xpathExpr = document.createExpression("//div");
const xpathResult = xpathExpr.evaluate(document); // returns an XPathResult object
const nodeContext = document.querySelector("nav");
// Re-using the XPathExpression "xpathExpr"
const otherResult = xpathExpr.evaluate(nodeContext); // returns an XPathResult object

Specifications

SpecificationsStandards references are available on the canonical MDN page.

Browser compatibility

Browser compatibilityCompatibility data is available on the canonical MDN page.

See also