百度地图：监听地图缩放自动显示和隐藏的富文本标签

   var map = new BMap.Map("container");
    map.centerAndZoom(new BMap.Point(121.554586, 29.813444), 12);
    map.enableScrollWheelZoom();
    map.setMapStyle({style: 'grayscale'})

    //JSON数据接口;
    var markerArr = [
        {title: "商会", point: "121.554586,29.813444", id: "1", value: "14"},
        {title: "机场", point: "121.472724,29.823098", id: "2", value: "16"},
        {title: "邱隘", point: "121.734311,29.833625", id: "3", value: "19"}
    ];

    //调用富文本标签;
    getRichMaker(markerArr);


    //循环数据接口;
    function getRichMaker(markerArr) {
        for (var i = 0; i = 12) {
            map.clearOverlays();
        } else {
            getRichMaker(markerArr);
        }
    });

    /*获取行政区域边界
     * 1.仅支持省市县级别的边界读取，不支持乡镇级别;
     * 2.读取的是以百度地图API的边界数据，BD-09坐标系；
     * */
    function getBoundary(city_name) {
        //map.clearOverlays();
        var bdary = new BMap.Boundary();
        bdary.get(city_name, function (rs) {
            var count = rs.boundaries.length;
            if (count === 0) {
                alert('未能获取当前输入行政区域');
                return;
            }
            //目标行政区划遮罩层；
            var pointArray = [];
            for (var i = 0; i