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) {
                if (data[i].name != null && data[i].value != null) {
                    jQuery('<input type="hidden" name="' + data[i].name + '" value="' + data[i].value + '" />').appendTo(form);
                } else {
                    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) {
                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",s]);
                    } else
                        jQuery.handleError(s,status);
                } catch (e) {
                    status = "error";
                    jQuery.handleError(s,status,e);
                }

                // The request was completed
                if (s.global)
                    jQuery.event.trigger("ajaxComplete",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,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');
            }
            jQuery(form).submit();

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

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

    },uploadHttpData: function (r,type) {
        var data = !type;
        if (!type)
            data = r.responseText;
        if (type == "xml")
            data = r.responseXML;
        //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") {
            ////////////Fix the issue that it always throws the error "unexpected token '<'"///////////////  
            data = r.responseText;
            var start = data.indexOf(">");
            if (start != -1) {
                var end = data.indexOf("<",start + 1);
                if (end != -1) {
                    data = data.substring(start + 1,end);
                }
            }
            ///////////////////////////////////////////////////////////////////////////////////////////////  
            eval("data = " + data);
        }
        // evaluate scripts within html
        if (type == "html")
            jQuery("<div>").html(data).evalScripts();

        return data;
    },handleError: function (s,xhr,e) {
        // If a local callback was specified,fire it
        if (s.error) {
            s.error.call(s.context || s,e);
        }

        // Fire the global callback
        if (s.global) {
            (s.context ? jQuery(s.context) : jQuery.event).trigger("ajaxError",[xhr,s,e]);
        }
    }
})