jQuery.extend({
    createUploadIframe: function(id, uri)
    {
            //create frame
            var frameId = 'jUploadFrame' + id;
             
            if(window.ActiveXObject) {
                   if(jQuery.browser.version=="9.0" || jQuery.browser.version=="10.0"){
                        var io = document.createElement('iframe');
                        io.id = frameId;
                        io.name = frameId;
                    }else if(jQuery.browser.version=="6.0" || jQuery.browser.version=="7.0" || jQuery.browser.version=="8.0"){
                        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           
    },
    createUploadForm: function(id, fileElementId,data)
    {
        //create form   
        var formId = 'jUploadForm' + id;
        var fileId = 'jUploadFile' + id;
        var form = $('<form  action="" method="POST" name="' + formId + '" id="' + formId + '" enctype="multipart/form-data"></form>'); 
        if(typeof(fileElementId) == "string"){
            var oldElement = $('#' + fileElementId);
            var newElement = $(oldElement).clone(true);/*此部分解决只能上传一次的问题*/
            $(oldElement).attr('id', fileId);
            $(oldElement).before(newElement);
            $(oldElement).appendTo(form);
        }else{
            for(var i in fileElementId){  
                var oldElement = $('#' + fileElementId[i]);  
                var newElement = $(oldElement).clone();  
                $(oldElement).attr('id', fileId);  
                $(oldElement).before(newElement);  
                $(oldElement).appendTo(form);  
            }
        }
        //set attributes
        if (data) {
            for ( var i in data) {
                $('<input type="hidden" name="' + i + '" value="' + data[i] + '" />').appendTo(form);
            }
        }
         
        $(form).css('position', 'absolute');
        $(form).css('top', '-1200px');
        $(form).css('left', '-1200px');
        $(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,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", [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
                                        {
                                            $(io).remove();
                                            $(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 io = $('#' + frameId);
            var form = $('#' + formId);
            $(form).attr('action', s.url);
            $(form).attr('method', 'POST');
            $(form).attr('target', frameId);
            if(form.encoding)
            {
                form.encoding = 'multipart/form-data';              
            }
            else
            {               
                form.enctype = 'multipart/form-data';
            }           
            $(form).submit();
 
        } catch(e) 
        {           
            jQuery.handleError(s, xml, null, e);
        }
        if(window.attachEvent){
            document.getElementById(frameId).attachEvent('onload', uploadCallback);
        }
        else{
            document.getElementById(frameId).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" ){
            ////////////以下为新增代码///////////////  
            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);  
                }  
            }  
            ///////////以上为新增代码///////////////  
            eval( "data = " + data );
        // evaluate scripts within html
        }
 
        return data;
    },
        handleError: function( s, xhr, status, e )      {  
            // If a local callback was specified, fire it  
                    if ( s.error ) {  
                        s.error.call( s.context || s, xhr, status, e );  
                    }  
      
                    // Fire the global callback  
                    if ( s.global ) {  
                        (s.context ? jQuery(s.context) : jQuery.event).trigger( "ajaxError", [xhr, s, e] );  
                    }  
        }  
})