$j.extend({
    createUploadIframe: function (id, uri) {
        //create frame
        var frameId = 'jUploadFrame' + id;
        var iframeHtml = '<iframe id="' + frameId + '" name="' + frameId + '" style="position:absolute; top:-9999px; left:-9999px"';
        if (window.ActiveXObject) {
            if (typeof uri == 'boolean') {
                iframeHtml += ' src="' + 'javascript:false' + '"';
            }
            else if (typeof uri == 'string') {
                iframeHtml += ' src="' + uri + '"';
            }
        }
        iframeHtml += ' />';
        $j(iframeHtml).appendTo(document.body);
        return $j('#' + frameId).get(0);
    },
    createUploadForm: function (id, fileElementId, data) {
        //create form	
        var formId = 'jUploadForm' + id;
        var fileId = 'jUploadFile' + id;
        var form = $j('<form  action="" method="POST" name="' + formId + '" id="' + formId + '" enctype="multipart/form-data"></form>');
        if (data) {
            for (var i in data) {
                $j('<input type="hidden" name="' + i + '" value="' + data[i] + '" />').appendTo(form);
            }
        }
        var oldElement = $j('#' + fileElementId);
        var newElement = $j(oldElement).clone();
        $j(oldElement).attr('id', fileId);
        $j(oldElement).before(newElement);
        $j(oldElement).appendTo(form);
        //set attributes
        $j(form).css('position', 'absolute');
        $j(form).css('top', '-1200px');
        $j(form).css('left', '-1200px');
        $j(form).appendTo('body');
        return form;
    },
    ajaxFileUpload: function (s) {
        // TODO introduce global settings, allowing the client to modify them for all requests, not only timeout		
        s = $j.extend({}, $j.ajaxSettings, s);
        var id = new Date().getTime();
        var form = $j.createUploadForm(id, s.fileElementId, (typeof (s.data) == 'undefined' ? false : s.data));
        var io = $j.createUploadIframe(id, s.secureuri);
        var frameId = 'jUploadFrame' + id;
        var formId = 'jUploadForm' + id;
        // Watch for a new set of requests
        if (s.global && !$j.active++) {
            $j.event.trigger("ajaxStart");
        }
        var requestDone = false;
        // Create the request object
        var xml = {};
        if (s.global)
            $j.event.trigger("ajaxSend", [xml, s]);
        // Wait for a response to come back
        var uploadCallback = function (isTimeout) {
            var io = document.getElementById(frameId);
            try {
                if (io.contentWindow) {
                    if (!$j.support.cssFloat) {
                        xml.responseXML = io.contentWindow.document.body.innerHTML;
                    } else {
                        xml.responseXML = io.contentWindow.document.XMLDocument ? io.contentWindow.document.XMLDocument : io.contentWindow.document;
                    }
                } else if (io.contentDocument) {
                    xml.responseXML = io.contentDocument.document.XMLDocument ? io.contentDocument.document.XMLDocument : io.contentDocument.document;
                }
            } catch (e) {
                //$j.handleError(s, xml, null, e);
            }
            if (xml || isTimeout == "timeout") {
                requestDone = true;
                var status;
                try {
                    status = isTimeout != "timeout" ? "success" : "error";
                    // Make sure that the request was successful or notmodified
                    if (status != "error") {
                        // process the data (runs the xml through httpData regardless of callback)
                        var data = $j.uploadHttpData(xml);
                        // If a local callback was specified, fire it and pass it the data
                        if (s.success)
                            s.success(data, status);
                        // Fire the global callback
                        if (s.global)
                            $j.event.trigger("ajaxSuccess", [xml, s]);
                    }
                    //else
                    //$j.handleError(s, xml, status);
                } catch (e) {
                    status = "error";
                    //$j.handleError(s, xml, status, e);
                }
                // The request was completed
                if (s.global)
                    $j.event.trigger("ajaxComplete", [xml, s]);
                // Handle the global AJAX counter
                if (s.global && ! --$j.active)
                    $j.event.trigger("ajaxStop");
                // Process result
                if (s.complete)
                    s.complete(xml, status);
                $j(io).unbind();
                setTimeout(function () {
                    try {
                        $j(io).remove();
                        $j(form).remove();
                    } catch (e) {
                        //$j.handleError(s, xml, null, e);
                    }
                }, 100);
                xml = null;
            }
        }
        // Timeout checker
        if (s.timeout > 0) {
            setTimeout(function () {
                // Check to see if the request is still happening
                if (!requestDone) uploadCallback("timeout");
            }, s.timeout);
        }
        try {
            var form = $j('#' + formId);
            $j(form).attr('action', s.url);
            $j(form).attr('method', 'POST');
            $j(form).attr('target', frameId);
            if (form.encoding) {
                $j(form).attr('encoding', 'multipart/form-data');
            }
            else {
                $j(form).attr('enctype', 'multipart/form-data');
            }
            $j(form).submit();
        } catch (e) {
            //$j.handleError(s, xml, null, e);
        }
        $j('#' + frameId).load(uploadCallback);
        return { abort: function () { } };
    },
    uploadHttpData: function (r) {
        if (!$j.support.cssFloat) {
            return $j(r.responseXML).find(".tx").text();
        }
        else {
            return $j(r.responseXML).find('UploadFileResult').text();
        }
    }
})