XPathEvaluator.createExpression()

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

Syntax

XPathExpression XPathEvaluator.createExpression(expression, resolver);

Parameters

expression

A DOMString representing representing the XPath expression to be created.

resolver Optional

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.

Example

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

HTML

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

JavaScript

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

Result

Specifications

Browser compatibility

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See also

• Document.createExpression()
• XPathExpression