XPathEvaluator: createExpression() method
This method compiles an XPathExpression
which can then be used for
(repeated) evaluations of the XPath expression.
Syntax
js
createExpression(expression)
createExpression(expression, resolver)
Parameters
expression
-
A string 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.
Examples
The following example shows the use of the evaluate()
method.
HTML
html
<div>XPath example</div>
<div>Number of <div>s: <output></output></div>
JavaScript
js
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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