上传完成回调complete方法返回获取不到

[fpleihub]

complete: function (task, state, responseText)
该回调中responseText为responseText=undefined

返回：
String jsonStr = "{"success": 1, "message":"上传成功","url":"" + files.get(0)+ ""}";
out.write(jsonStr);

求解

[devin87]

检查是否跨域了