Add-ons

IsDefaultNamespace

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 addons.mozilla.org (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.

The following is a snippet to get isDefaultNamespace() supported across other browsers.

Note that all Gecko-based browsers (including Firefox) support Node.isDefaultNamespace. This function is not necessary for Gecko-based browsers (though the function will quickly return the standard value for Mozilla browsers).
// http://www.w3.org/TR/DOM-Level-3-Core/core.html#Node3-isDefaultNamespace
// http://www.w3.org/TR/DOM-Level-3-Core/namespaces-algorithms.html#isDefaultNamespaceAlgo

function isDefaultNamespace(node, namespaceURI) {
    if (node.isDefaultNamespace) {
        return node.isDefaultNamespace(namespaceURI);
    }
    switch (node.nodeType) {
        case 1: //  ELEMENT_NODE
            if (!node.prefix) {
                return (node.namespaceURI === namespaceURI);
            }
            if (node.attributes.length) {
                for (var i=0; i < node.attributes.length; i++) {
                    var att = node.attributes[i];
                    if (att.localName === 'xmlns') {
                        return att.value === namespaceURI;
                    }
                }
            }
            if (node.parentNode) {
            // EntityReferences may have to be skipped to get to it
                return isDefaultNamespace(node.parentNode, namespaceURI);
            }
            else {
                return false; // unknown;
            }
        case 9: // DOCUMENT_NODE
            return isDefaultNamespace(node.documentElement, namespaceURI);
        case 6: // ENTITY_NODE
        case 12: // NOTATION_NODE
        case 10: // DOCUMENT_TYPE_NODE
        case 11: // DOCUMENT_FRAGMENT_NODE
            return false; // unknown
        case 2: // ATTRIBUTE_NODE:
            if (node.ownerElement ) {
                return isDefaultNamespace(node.ownerElement , namespaceURI);
            }
            else {
                return false; // unknown
            }
        default:
            if (node.parentNode) {
            // EntityReferences may have to be skipped to get to it
                return isDefaultNamespace(node.parentNode, namespaceURI);
            }
            else {
                return false; // unknown
            }
    }
}

 

Document Tags and Contributors

 Contributors to this page: bunnybooboo, wbamberg, Brettz9
 Last updated by: bunnybooboo,