ajax异步上传图片但请求无响应，已经贴出代码，各位大神帮忙分析下！！

[Michael_hu520]

var url= "<%=request.getContextPath()%>/webhelp/relaImgController.do?cmd=uploadLifeImage&type=upload&imgCde=LF&cId="+cId+"&fileId="+imgId;
$.ajaxFileUpload({
url: url,
type: 'post',
secureuri: false,
fileElementId: ['up_img1','up_img2','up_img3','up_img4'],
dataType: 'json',
success: function(data, status){
hiddenMessage();
if(data.message=="true"){
document.getElementById("massage_box").style.display = "none";
document.getElementById("up_imgId1").style.display = "none";
document.getElementById("up_imgId2").style.display = "none";
document.getElementById("up_imgId3").style.display = "none";
document.getElementById("up_imgId4").style.display = "none";
// document.getElementById("up_imgId5").style.display = "none";
document.getElementById("blUpload").value = "Y";
document.getElementById("up_imgBtn").style.display = "none";
document.getElementById("re_imgBtn").style.display = "";
alert("上传成功!");
}else if(data.message.indexOf("false")>0 || data.message == "" || typeof(data.message) == "undefined"){
document.getElementById("blUpload").value = "";
alert("上传失败!");
}else{
document.getElementById("blUpload").value = "";
alert(data.message);
}

}
}