ajaxForm提交不进回调函数....

这是JS代码:普通字段完全没问题也会走回调函数,但是只要一上传文件就不会进回调函数了,后台文件也上传了,数据库也保存了...............求大神帮忙!!!!
if($('#threedDocumentForm').form('validate')){
var subForm = function(){
var url = "";
if('${threeDtech.id}' != ''){
url = "ThreeDtechAction_updateThreeDtech";
}else{
url = "ThreeDtechAction_saveThreeDtech";
}
//表单参数
alert(url);
var options = {
url:url,
dataType: 'json',
success:cc
};
//ajaxForm方式提交表单
$("#threedDocumentForm").ajaxSubmit(options);
};
function cc(result){//提交后的回调函数
alert(result);
if(result.success){
$('#threeDtechReleaseDialog').dialog('close');
$.messager.show({title:'提示',msg:result.msg});
threeDtechGrid.datagrid('reload');
}else{
$.messager.show({title:'提示',msg:result.msg});
}
}

}