AJAX提交数据到后台，PHP无法获取POST数据的解决办法

1.

$.ajax({
    type: "POST",
    url: "api/GameAjax/getLuckyGift",
    data: {openid: $("#openid").val(), rid: $("#rid").val()},
    success: function (data) {

    }

});

无法获取$_POST

2.

$.ajax({
    type: "POST",
    url: "api/GameAjax/getLuckyGift/index.php",
    data: {openid: $("#openid").val(), rid: $("#rid").val()},
    success: function (data) {

    }

});

url加上具体index.php路径后，能获取 $_POST