This is an archived page. It's not actively maintained.



Support for extensions using XUL/XPCOM or the Add-on SDK was removed in Firefox 57, released November 2017. As there is no supported version of Firefox enabling these technologies, this page will be removed by December 2020.

Add-ons using the techniques described in this document are considered a legacy technology in Firefox. Don't use these techniques to develop new add-ons. Use WebExtensions instead. If you maintain an add-on which uses the techniques described here, consider migrating it to use WebExtensions.

Starting from Firefox 53, no new legacy add-ons will be accepted on (AMO) for desktop Firefox and Firefox for Android.

Starting from Firefox 57, only extensions developed using WebExtensions APIs will be supported on Desktop Firefox and Firefox for Android.

Even before Firefox 57, changes coming up in the Firefox platform will break many legacy extensions. These changes include multiprocess Firefox (e10s), sandboxing, and multiple content processes. Legacy extensions that are affected by these changes should migrate to use WebExtensions APIs if they can. See the "Compatibility Milestones" document for more information.

A wiki page containing resources, migration paths, office hours, and more, is available to help developers transition to the new technologies.


Notes and sample code for XPath and Ajax

(The following was moved from document.evaluate)


//obj and contextNode should be the same object, if context is a ajax xml object (example: returnedXML)
 this should be used as :


//contextNode should be used in the one in which it was created

//add by mooring 2008-11-15 16:00 china

var xhr = new Ajax('post','demo.xml',parseXML,'xml');
//Ajax is a class written by javascript  which return responseXML object to parseXML function
 function parseXML(obj)//obj is the returnXML object now
		alert("Your Browser does't support this script!");

	var fields = [];//store the results
		var tobj = obj.documentElement.selectNodes("/root/field/item");
		for(var i=0;i<tobj.length; i++)
		var tobj = obj.evaluate("/root/field/item",obj.documentElement,null, XPathResult.ANY_TYPE, null);
		var tmp = tobj.iterateNext();
			tmp = tobj.iterateNext();
	}        alert(fields);
//here is the demo xml file for xpath
<?xml version="1.0"?>

//add by mooring 2008-11-15 16:16 china