jQuery.extend({



    createUploadIframe: function(id, uri){



            var frameId = 'jQuery' + id;

            

            if(window.ActiveXObject) {

                var io = document.createElement('<iframe id="' + frameId + '" name="' + frameId + '" />');



                if(typeof uri== 'boolean'){

                    io.src = 'javascript:false';

                }

                else if(typeof uri== 'string'){

                    io.src = uri;

                }

            }

            else {

                var io = document.createElement('iframe');

                io.id = frameId;

                io.name = frameId;

            }



            io.style.position = 'absolute';

            io.style.top = '-1000px';

            io.style.left = '-1000px';



            document.body.appendChild(io);



            return io



    },



    ajaxUpload: 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()

        io = jQuery.createUploadIframe(id, s.secureuri)



        // 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){

            try {

                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;

            }

            catch(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(){ document.body.removeChild(io); }, 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 frameId = 'jQuery' + id;

            var io = document.getElementById(frameId);

            // Initialize the HTML form properties in case they are

            // not defined in the HTML form.

            s.uploadform.action = s.url;

            s.uploadform.method = 'POST';

            s.uploadform.target = frameId;



            if(s.uploadform.encoding){

                // IE does not respect property enctype for HTML forms.

                // Instead use property encoding.

                s.uploadform.encoding = 'multipart/form-data';

            }

            else{

                s.uploadform.enctype = 'multipart/form-data';

            }



            s.uploadform.submit();



        } catch(e) {

            jQuery.handleError(s, xml, null, e);

        }



        if(window.attachEvent){

            io.attachEvent('onload', uploadCallback);

        }

        else{

            io.addEventListener('load', uploadCallback, false);

        }       

        

        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 );



        // evaluate scripts within html

        if ( type == "html" )

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



        return data;

    }

})