报错：
 No 'Access-Control-Allow-Origin' header is present on the requestedresource. Origin 'http://127.0.0.1:8020' is therefore not allowed access. The response had HTTP status code 503.
 方法:
      $.ajax({
            type:"post",
            url:dataUrl.addDeliveraddress,
            dataType:"json",
            data:str,
            statusCode:{
                200:function(data){
                alert("成功");
                },
                404:function(data){
                    alert("404");
                },
                503:function(){
                    alert("添加失败");
                },
            }
            
        });

只能判断200或者404，503跟本抓取不到求解决