怎样用AjaxSubmit()提交file文件

$("#formId").submit(
  $(this).ajaxSubmit({
    url:...,
    type:...,
    success:function(){
    ...
    }
  });
  return false;//阻止自动提交
);

var opt = {
  type:'post',            
  datatype:'json',
  url:'../../../rybmanagement/upLoadFile',            
  success: function(data) {
  ...
  }
};
$("#formId").ajaxSubmit(opt);//相当于from.submit()

<script src="jquery-form.js" type="text/javascript"></script>
<script src="../../js/jquery-2.1.1.min.js"></script>