Difference between revisions of "XPath"

From GreaseSpot Wiki
Jump to navigationJump to search
(→‎More information: Renamed to "Links")
(added link to XPath Checker)
Line 20: Line 20:
* [http://www.zvon.org/xxl/XPathTutorial/General/examples.html XPath tutorial]
* [http://www.zvon.org/xxl/XPathTutorial/General/examples.html XPath tutorial]
* [http://en.wikipedia.org/wiki/XPath Wikipedia: XPath]
* [http://en.wikipedia.org/wiki/XPath Wikipedia: XPath]
* [https://addons.mozilla.org/en-US/firefox/addon/1095 XPath Checker (Firefox addon)]

Revision as of 06:56, 6 June 2007

XPath (XML Path Language) is a language for addressing elements in a XML or HTML document. XPath expressions describe paths in a tree represention of the document.

XPath is very fast compared to manual DOM traversal (see e.g. getElementsByClassName Speed Comparison).

This page is intended for tips and gotchas related to using XPath in Greasemonkey scripts, not complete documentation. See the links below for that.

Using XPath in Greasemonkey

The most convenient way to use XPath in Greasemonkey scripts is with a helper function. The insides of that function illustrate the less convenient way.

Relative paths

Note that relative XPath expressions, that start from some specific node, do not begin with a /. Start them with a period, e.g. .//a, or an axis, e.g. descendant::a. The default axis is child, so just a works to find an immediate descendant.