使用ajaxFileupload上传文件，将文件内容以json方式返回显示到浏览器。

问题：返回的文件内容较小时正常，但当返回的json数据大概大于10K后，返回到浏览器后弹出保存文件对话框，无法正常显示。经过测试，如果去掉上传文件功能，可以正常返回300K的json数据。

struts2设置response contentType 为text/html。另外设置为text/plain、application/json都有这个问题。

js代码：

$.ajaxFileUpload({

url:'${ctx}/domain/Reso!uploadFile.action',

secureuri:false,

fileElementId:'file',

dataType: 'json',

success: function (json){

var data = json.data;

$(data).each(function(i){

fillRecord(data[i].host,data[i].status,data[i].type);

//fillRecord是填充页面表格

});

},

error: function (data, status, e){

alert(e);

}

})

以下是ajaxfileupload.js代码：

jQuery.extend({

createUploadIframe: function(id, uri)

{

//create frame

var frameId = 'jUploadFrame' + id;

if(window.ActiveXObject) {

var io = document.createElement('');

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)

{

//create form

var formId = 'jUploadForm' + id;

var fileId = 'jUploadFile' + id;

var form = $('

');

var oldElement = $('#' + fileElementId);

var newElement = $(oldElement).clone();

$(oldElement).attr('id', fileId);

$(oldElement).before(newElement);

$(oldElement).appendTo(form);

//set attributes

$(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);

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" )

eval( "data = " + data );

// evaluate scripts within html

if ( type == "html" )

jQuery("