jquery_xhtml_hack.js

/**
 * Hack to allow jQuery to work within XHTML documents that define an xmlns
 */

/**
 * Use the given object to override the given methods in its prototype
 * with namespace-aware equivalents
 */
function addNS(obj, methods) {
    var proto = obj.constructor.prototype;
    var ns = document.documentElement.namespaceURI;
    
    for (var methodName in methods) {
        (function () {
            var methodNS = proto[methodName + "NS"];

            if (methodNS) {
                proto[methodName] = function () {
                    var args = Array.prototype.slice.call(arguments, 0);
                    args.unshift(ns);
                    return methodNS.apply(this, args);
                };
            }
        })();
    }
}

// Play nice with IE -- who doesn't need this hack in the first place
if (document.constructor) {
    // Override document methods that are used by jQuery
    addNS(document, {
        createElement: 1,
        getElementsByTagName: 1
    });

    // Override element methods that are used by jQuery
    addNS(document.createElement("div"), {
        getElementsByTagName: 1,
        getAttribute: 1,
        getAttributeNode: 1,
        removeAttribute: 1,
        setAttribute: 1
    });
}

Can you provide a usage example? For example, how would I use this to read a fb:loginbutton tag with jQuery?