leaflet 显示更高层的瓦片

leaflet 开源的交互式地图库。

 var CHINA = "./images/{z}/{x}/{y}.jpg";
         var CHINAtdt = L.tileLayer(CHINA, {
             attribution: "地图",
             minZoom: 18,
             maxNativeZoom: 22, //显示22级
             maxZoom: 22,
         });