layui 弹出层值回传解决方式

layer.open({
   type: 2,
   title: "设置围栏",
   shadeClose: true,
   shade: 0.4,
   area: ['90%', '90%'],
   content: "/ElectronicFence/Map?id=" + id + "&shapeType=" + shapeType,
   btn: ['确定','关闭'],
   yes: function(index){
   //当点击‘确定'按钮的时候，获取弹出层返回的值
   var res = window["layui-layer-iframe" + index].callbackdata();
   //打印返回的值，看是否有我们想返回的值。
   console.log(res);
   //关闭弹出层
   layer.close(index);
   },
   cancel: function(){
   //右上角关闭回调
   }
  });
 

var res = window["layui-layer-iframe" + index].callbackdata();

<script>
 var callbackdata = function () {
  var data = {
  username: 'zhangfj'
  };
  return data;
 }
 </script>