PHP tp5 ajax 返回的是整个html页面

问题代码

 $.ajax({
            type:"POST",
            url:"index/Comment/add",
            data:{"id":3,"user":user},
            dataType: "json",
            success:function (res) {
                console.log("ajax");

                console.log(res);
            }
        });

现象：

解决：

  $.ajax({
            type:"POST",
            url:"/index/Comment/add",
            data:{"id":3,"user":user},
            dataType: "json",
            success:function (res) {
                console.log("ajax");

                console.log(res);
            }
        });