User:Marti/Greasemonkey Manual Addendum/XPathResult
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[edit] Description
XPathResult is added so that document.evaluate() works. Referential link to source code where this is part of the API is currently at #L253. Currently MDC does not have full reference and this article is key to interpreting not only the constants to values mapping but also why one would want to use the different types. When MDC is fully documented this page may be removed from this personal workspace.
[edit] Syntax
document.evaluate( xpathExpression, contextNode, namespaceResolver, XPathResult.resultType, XPathResult );
- Value: Object
- Returns: XPathResult
- Compatibility: Greasemonkey 0.6+
- All properties, methods and constants are optional
[edit] Properties
[edit] booleanValue
- Value: Boolean (readonly boolean)
- Usage:
alert( "Found a boolean with a value of " + XPathResult.booleanValue );- This is typically used if the XPathResult.BOOLEAN_TYPE resultType is used in document.evaluate to request a single boolean based off the xpathExpression.
[edit] invalidIteratorState
- Value: Boolean (readonly boolean)
- Usage:
if (XPathResult.invalidIteratorState) { /* some code */ }- Use this to test if the DOM has been modified since last iteration (e.g. the last document.evaluate). If true then the current iteration in XPathResult may not include these recent changes.
[edit] numberValue
- Value: Number (readonly float)
- Usage:
alert( "Found a number with a value of " + XPathResult.numberValue );- This is typically used if the XPathResult.NUMBER_TYPE resultType is used in document.evaluate to request a single number based off the xpathExpression.
[edit] resultType
- Value: Number (readonly short)
- Usage:
if (XPathResult.resultType == XPathResult.UNORDERED_NODE_SNAPSHOT_TYPE) { /* some code * }- See resultType Constants for available resultTypes.
[edit] singleNodeValue
- Value: Object (readonly Node)
- Usage:
alert( XPathResult.singleNodeValue.textContent );- This is typically used if the XPathResult.FIRST_ORDERED_NODE_TYPE resultType used in document.evaluate requests a single node based off the xpathExpression.
[edit] snapshotLength
- Value: Number (readonly int)
- Usage:
if (XPathResult.snapshotLength > 0) { /* some code */ }
[edit] stringValue
- Value: String (readonly String)
- Usage:
alert( "Found a string with a value of " + XPathResult.stringValue );- This is typically used if the XPathResult.STRING_TYPE resultType is used in document.evaluate to request a single string based off the xpathExpression.
[edit] Methods
[edit] iterateNext
- Usage:
var thisNode = XPathResult.iterateNext(); - Returns: Object (Node)
[edit] snapshotItem
- Usage:
var thisNode = XPathResult.snapshotItem( index ); - Returns: Object (Node)
[edit] resultType Constants
[edit] ANY_TYPE
- Value: Number (readonly short)
- Constant: 0
- Usage:
document.evaluate( xpathExpression, contextNode, namespaceResolver, XPathResult.ANY_TYPE, XPathResult);
[edit] NUMBER_TYPE
- Value: Number (readonly short)
- Constant: 1
- Usage:
document.evaluate( xpathExpression, contextNode, namespaceResolver, XPathResult.NUMBER_TYPE, XPathResult);
[edit] STRING_TYPE
- Value: Number (readonly short)
- Constant: 2
- Usage:
document.evaluate( xpathExpression, contextNode, namespaceResolver, XPathResult.STRING_TYPE, XPathResult);
[edit] BOOLEAN_TYPE
- Value: Number (readonly short)
- Constant: 3
- Usage:
document.evaluate( xpathExpression, contextNode, namespaceResolver, XPathResult.BOOLEAN_TYPE, XPathResult);
[edit] UNORDERED_NODE_ITERATOR_TYPE
- Value: Number (readonly short)
- Constant: 4
- Usage:
document.evaluate( xpathExpression, contextNode, namespaceResolver, XPathResult.UNORDERED_NODE_ITERATOR_TYPE, XPathResult);
[edit] ORDERED_NODE_ITERATOR_TYPE
- Value: Number (readonly short)
- Constant: 5
- Usage:
document.evaluate( xpathExpression, contextNode, namespaceResolver, XPathResult.ORDERED_NODE_ITERATOR_TYPE, XPathResult);
[edit] UNORDERED_NODE_SNAPSHOT_TYPE
- Value: Number (readonly short)
- Constant: 6
- Usage:
document.evaluate( xpathExpression, contextNode, namespaceResolver, XPathResult.UNORDERED_NODE_SNAPSHOT_TYPE, XPathResult);
[edit] ORDERED_NODE_SNAPSHOT_TYPE
- Value: Number (readonly short)
- Constant: 7
- Usage:
document.evaluate( xpathExpression, contextNode, namespaceResolver, XPathResult.ORDERED_NODE_SNAPSHOT_TYPE, XPathResult);
[edit] ANY_UNORDERED_NODE_TYPE
- Value: Number (readonly short)
- Constant: 8
- Usage:
document.evaluate( xpathExpression, contextNode, namespaceResolver, XPathResult.ANY_UNORDERED_NODE_TYPE, XPathResult);
[edit] FIRST_ORDERED_NODE_TYPE
- Value: Number (readonly short)
- Constant: 9
- Usage:
document.evaluate( xpathExpression, contextNode, namespaceResolver, XPathResult.FIRST_ORDERED_NODE_TYPE, XPathResult);
[edit] Examples
// Log all snapshot second level headers (h2) tag element text nodes to the error console in reverse order for speed.
var xpr = document.evaluate("//h2", document, null, XPathResult.ORDERED_NODE_SNAPSHOT_TYPE, null);
for (var i = xpr.snapshotLength - 1; i >= 0; --i)
GM_log( xpr.snapshotItem(i).textContent );
/* Log all live second level headers (h2) tag element text nodes to the error console - Alternate method */
var xpr;
document.evaluate("//h2", document, null, XPathResult.ORDERED_NODE_ITERATOR_TYPE, xpr);
var thisNode;
while ((thisNode = xpr.iterateNext()))
GM_log( thisNode.textContent );
