ajax图片单个上传（ajaxfileupload.js）

function doUpload(o){

        $(o).attr(‘name‘,‘userphoto‘)
        $(o).attr(‘id‘,‘userphoto‘)
        o = (o.attributes[‘bin‘].nodeValue)
        if(o == ‘a‘){
           //填充一个假地址
           $("#showpage_sty_1").val(‘ed‘);
           upload(‘/StoreManage/upload/key/showimage/tempname/userphoto‘,‘show_1‘,‘userphoto‘);
        }else if(o =="b"){
            $("#showpage_sty_2").val(‘ed‘);
            upload(‘/StoreManage/upload/key/ewmimage/tempname/userphoto‘,‘show_2‘,‘userphoto‘);
        }else if(o == ‘c‘){
            $("#showpage_sty_3").val(‘ed‘);
            upload(‘/StoreManage/upload/key/showimage/tempname/userphoto‘,‘show_3‘,‘userphoto‘);
        }
    }

function upload(url,replaceUrl,fileElementId){

    $.ajaxFileUpload
    (
        {
            url:url, //用于文件上传的服务器端请求地址
            secureuri: false, //一般设置为false
            fileElementId: fileElementId, //文件上传空间的id属性  <input type="file" id="file" name="file" />
            dataType: ‘HTML‘, //返回值类型 一般设置为json
            success: function (data, status)  //服务器成功响应处理函数
            {
                if(data != "error"){
                    $("#"+replaceUrl).attr(‘src‘,data);
                }
                //无需理解这段代码。为了上传。
                if(replaceUrl == ‘show_1‘){
                    $(":file").eq(0).removeAttr(‘name‘)
                    $(":file").eq(0).removeAttr(‘id‘)
                }else if(replaceUrl == ‘show_2‘){
                    $(":file").eq(1).removeAttr(‘name‘)
                    $(":file").eq(1).removeAttr(‘id‘)
                }else{
                    $(":file").eq(2).removeAttr(‘name‘)
                    $(":file").eq(2).removeAttr(‘id‘)
                }
            },
            error: function (data, status, e)//服务器响应失败处理函数
            {
                alert(e);
            }
        }
    )
}

jQuery.extend({
    
　　//在方法内创建添加一个iframe　　
　　
    //style="position:absolute; top:-9999px; left:-9999px" 让其在界面上看不见
    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   创建表单，
        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);//取到之前的 也就是我们传过来的 file的id 
        var newElement = jQuery(oldElement).clone();//把代码克隆过来
        jQuery(oldElement).attr(‘id‘, fileId);//修改了原来的file的ID 属性
        jQuery(oldElement).before(newElement);//在旧的file前面加上新的file对象
        jQuery(oldElement).appendTo(form);//把原来的对象传入到创建的表单中去

　　　　　　//问题应该就在这里 在这里完成  file的克隆， 只有一种可能，那就是当第一个图片传递完成之后，当第二次点击传第二张图片的时候，依旧这里取得还是第一个的file 所以才会为空。
　　　　      问题应该出在，file id 没有动态对应好。
        
        //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);
　　　　　　//分别穿件 form 和 iframe
        var frameId = ‘jUploadFrame‘ + id;
        var formId = ‘jUploadForm‘ + id;    
　　　　　　    
        // Watch for a new set of requests
        if ( s.global && ! jQuery.active++ )
        {
            jQuery.event.trigger( "ajaxStart" ); //触发ajaxStart方法
        }            
        var requestDone = false;
        // Create the request object
        var xml = {}   
        if ( s.global )
            jQuery.event.trigger("ajaxSend", [xml, s]);//触发ajaxSend方法
        // Wait for a response to come back

　　　　　　//回调函数
        var uploadCallback = function(isTimeout)
        {            
            var io = document.getElementById(frameId);//获取iframe 对象
            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;
　　　　　　　　　　//请求状态 成功 或者 不成功，
                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();//去除穿件的iframe 实际上应该是去除remove就够了.
                                            jQuery(form).remove(); //去除创建的 from 表单
                                            
                                        } 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 );
        // evaluate scripts within html
        if ( type == "html" )
            jQuery("<div>").html(data).evalScripts();

        return data;
    }
})