layui.open子页面下拉框无法赋值

layer.open({      type: 2,      title: ‘下拉框选中’,      maxmin: false,      skin: ‘layui-layer-lan’,      shadeClose: true, //点击遮罩关闭层      area : [‘50%’ , ‘56%’],      content:’/index/1’,//弹框显示的url,对应的页面      success : function(layero, index)                  layui.form.render();                  var iframe = layero.find(‘iframe’)[0].contentWindow;                   var body = layui.layer.getChildFrame(‘body’, index);                   body.find("#type").val(3);                   iframe.layui.form.render(‘select’);       }});