获取layer.open弹出层的返回值方法

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 type="text/javascript">
  var map = new AMap.Map("container", {
   resizeEnable: true
  });
  //在地图中添加MouseTool插件
  var mouseTool = new AMap.MouseTool(map);
  AMap.event.addDomListener(document.getElementById('point'), 'click', function () {
   mouseTool.marker({ offset: new AMap.Pixel(-14, -11) });
  }, false);
  AMap.event.addDomListener(document.getElementById('line'), 'click', function () {
   mouseTool.polyline();
  }, false);
  AMap.event.addDomListener(document.getElementById('polygon'), 'click', function () {
   mouseTool.polygon();
  }, false);


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