ajax异步上传

jQuery.extend({
    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] );
                }
    },
    createUploadIframe: function(id, uri)
    {

        var frameId = 'jUploadFrame' + id;

        if(window.ActiveXObject) {
            if(jQuery.browser.version=="9.0")
            {
                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;        
    },
    ajaxUpload:function(s,xml){
        //if((fromFiles.nodeType&&!((fileList=fromFiles.files)&&fileList[0].name)))

        var uid = new Date().getTime(),idIO='jUploadFrame'+uid,_this=this;
        var jIO=$('<iframe name="'+idIO+'" id="'+idIO+'" style="display:none">').appendTo('body');
        var jForm=$('<form action="'+s.url+'" target="'+idIO+'" method="post" enctype="multipart/form-data"></form>').appendTo('body');
        var oldElement = $('#'+s.fileElementId);
        var newElement = $(oldElement).clone();
        $(oldElement).attr('id', 'jUploadFile'+uid);
        $(oldElement).before(newElement);
        $(oldElement).appendTo(jForm);

        this.remove=function()
        {
            if(_this!==null)
            {
                jNewFile.before(jOldFile).remove();
                jIO.remove();jForm.remove();
                _this=null;
            }
        }
        this.onLoad=function(){

            var data=$(jIO[0].contentWindow.document.body).text();


            try{

                if(data!=undefined){
                    data = eval('(' + data + ')');
                    try {

                        if (s.success)
                            s.success(data, status);

                        // Fire the global callback
                        if(s.global)
                            jQuery.event.trigger("ajaxSuccess", [xml, s]);
                        if (s.complete)
                            s.complete(data, status);
                        xml = null;
                      } 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

                }
         }catch(ex){
              alert(ex.message);
         };
        }
        this.start=function(){jForm.submit();jIO.load(_this.onLoad);};
        return this;

    },
    createUploadForm: function(id, url,fileElementId, data)
    {
        //create form    
        var formId = 'jUploadForm' + id;
        var fileId = 'jUploadFile' + id;
        var form = jQuery('<form  action="'+url+'" 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    
        // Create the request object
        var xml = {};
        s = jQuery.extend({}, jQuery.ajaxSettings, s);
        if(window.ActiveXObject){
            var upload =  new jQuery.ajaxUpload(s,xml);
            upload.start();

       }else{
        var id = new Date().getTime();
        var form = jQuery.createUploadForm(id,s.url, 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;

        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]);
                        if (s.complete)
                            s.complete(data, status);

                    } 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
                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');            
                    }    


                    jQuery(form).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).html() );
        }
        // evaluate scripts within html
        if ( type == "html" )
            jQuery("<div>").html(data).evalScripts();

        return data;
    }
});