Custom YUI3 IO Utlity io upload iframe that returns HTML

YUI.add('customyuiiouploadiframe', function(Y) {

    var w = Y.config.win,
        d = Y.config.doc,
        _std = (d.documentMode && d.documentMode >= 8),
        _d = decodeURIComponent,
        _end = Y.IO.prototype.end;


    /**
     * Creates the iframe transported used in file upload
     * transactions, and binds the response event handler.
     *
     * @method _cFrame
     * @private
     * @param {Object} o Transaction object generated by _create().
     * @param {Object} c Configuration object passed to YUI.io().
     * @param {Object} io
     */
    function _cFrame(o, c, io) {
        var i = Y.Node.create('<iframe src="#" id="io_iframe' + o.id + '" name="io_iframe' + o.id + '" />');
            i._node.style.position = 'absolute';
            i._node.style.top = '-1000px';
            i._node.style.left = '-1000px';
            Y.one('body').appendChild(i);
        // Bind the onload handler to the iframe to detect the file upload response.
        Y.on("load", function() { io._uploadComplete(o, c); }, '#io_iframe' + o.id);
    }

    /**
     * Removes the iframe transport used in the file upload
     * transaction.
     *
     * @method _dFrame
     * @private
     * @param {Number} id The transaction ID used in the iframe's creation.
     */
    function _dFrame(id) {
        Y.Event.purgeElement('#io_iframe' + id, false);
        Y.one('body').removeChild(Y.one('#io_iframe' + id));
    }

    Y.IO.prototype._uploadComplete = function(o, c) {
        var io = this,
            d = Y.one('#io_iframe' + o.id).get('contentWindow.document'),
            b = d.one('body'),
            p;

        if (c.timeout) {
            io._clearUploadTimeout(o.id);
        }

        try {
            if (b) {
                // When a response Content-Type of "text/plain" is used, Firefox and Safari
                // will wrap the response string with <pre></pre>.
                p = b.one('pre:first-child');
                o.c.responseText = p ? p.innerHTML.get('text') : b.get('text');
                o.c.responseHTML = p ? p.innerHTML.get('innerHTML') : b.get('innerHTML');
            }
            else {
                o.c.responseXML = d._node;
            }
        }
        catch (e) {
            o.e = "upload failure";
        }

        io.complete(o, c);
        io.end(o, c);
        // The transaction is complete, so call _dFrame to remove
        // the event listener bound to the iframe transport, and then
        // destroy the iframe.
        w.setTimeout( function() { _dFrame(o.id); }, 0);
    }

}, '1.0.0', { requires: [ 'io-upload-iframe' ] });