jQuery.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 += ' />';
        jQuery(iframeHtml).appendTo(document.body);

        return jQuery('#' + frameId).get(0);
    },
    createUploadForm: function (id, fileElementId, data) {
        //create form	
        var formId = 'jUploadForm' + id;
        var fileId = 'jUploadFile' + id;
        var form = jQuery('<form  action="" method="POST" name="' + formId + '" id="' + formId + '" enctype="multipart/form-data"></form>');
        if (data) {
            for (var i in data) {
                jQuery('<input type="hidden" name="' + i + '" value="' + data[i] + '" />').appendTo(form);
            }
        }
        var oldElement = jQuery('#' + fileElementId);
        var newElement = jQuery(oldElement).clone();
        jQuery(oldElement).attr('id', fileId);
        jQuery(oldElement).before(newElement);
        jQuery(oldElement).appendTo(form);



        //set attributes
        jQuery(form).css('position', 'absolute');
        jQuery(form).css('top', '-1200px');
        jQuery(form).css('left', '-1200px');
        jQuery(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 = jQuery.extend({}, jQuery.ajaxSettings, s);
        var id = new Date().getTime()
        var form = jQuery.createUploadForm(id, s.fileElementId, (typeof (s.data) == 'undefined' ? false : s.data));
        var io = jQuery.createUploadIframe(id, s.secureuri);
        var frameId = 'jUploadFrame' + id;
        var formId = 'jUploadForm' + id;
        // Watch for a new set of requests
        if (s.global && !jQuery.active++) {
            jQuery.event.trigger("ajaxStart");
        }
        var requestDone = false;
        // Create the request object
        var xml = {}
        if (s.global)
            jQuery.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) {
                xml.responseText = io.contentWindow.document.body ? io.contentWindow.document.body.innerHTML : null;
                xml.responseXML = io.contentWindow.document.XMLDocument ? io.contentWindow.document.XMLDocument : io.contentWindow.document;

            } else if (io.contentDocument) {
                xml.responseText = io.contentDocument.document.body ? io.contentDocument.document.body.innerHTML : null;
                xml.responseXML = io.contentDocument.document.XMLDocument ? io.contentDocument.document.XMLDocument : io.contentDocument.document;
            }
            //}catch(e)
            //{
            //alert(e);
            //jQuery.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 = jQuery.uploadHttpData(xml, s.dataType);
                    // 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)
                        jQuery.event.trigger("ajaxSuccess", [xml, s]);
                } //else
                //jQuery.handleError(s, xml, status);
                //   } catch(e) 
                //	{
                //      status = "error";

                //jQuery.handleError(s, xml, status, e);
                //}

                // The request was completed
                if (s.global)
                    jQuery.event.trigger("ajaxComplete", [xml, s]);

                // Handle the global AJAX counter
                if (s.global && ! --jQuery.active)
                    jQuery.event.trigger("ajaxStop");

                // Process result
                if (s.complete)
                    s.complete(xml, status);

                jQuery(io).unbind()

                setTimeout(function () {	//try 
                    //{
                    jQuery(io).remove();
                    jQuery(form).remove();

                    //} catch(e) 
                    //{
                    //jQuery.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 = jQuery('#' + formId);
        jQuery(form).attr('action', s.url);
        jQuery(form).attr('method', 'POST');
        jQuery(form).attr('target', frameId);
        if (form.encoding) {
            jQuery(form).attr('encoding', 'multipart/form-data');
        }
        else {
            jQuery(form).attr('enctype', 'multipart/form-data');
        }
        $('#' + formId).submit();

        //  } catch(e) 
        //	{			
        //jQuery.handleError(s, xml, null, e);
        //  }

        jQuery('#' + frameId).load(uploadCallback);
        return { abort: function () { } };

    },

    uploadHttpData: function (r, type) {
        var data = !type;
        data = type == "xml" || data ? r.responseXML : r.responseText;

        // If the type is "script", eval it in global context
        if (type == "script")
            jQuery.globalEval(data);
        // Get the JavaScript object, if JSON is used.
        if (type == "json") {
            eval("data = " + $(data).text());
            //eval("data = " + data.replace('<pre', '').replace('</pre>', ''));
        }
        // evaluate scripts within html

        if (type == "html")
            jQuery("<div>").html(data).evalScripts();

        return data;
    }
})