关键代码：

/// <reference path="MarkerManager.js" />BMapLib.MarkerManager.prototype.count = function () {    /// <summary>    /// 获取MarkerManager管理标记数量    /// </summary>    /// <returns type="">管理标记数量</returns>    return this._numMarkers.length;}BMapLib.MarkerManager.prototype.find = function (properties, value) {    /// <summary>    ///查找标记     /// </summary>    /// <param name="properties">键</param>    /// <param name="value">值</param>    /// <returns type="BMap.Marker">若没查找到，则返回NULL</returns>    for (var i = 0; i < this._numMarkers.length; i++) {        var marker = this._numMarkers[i];        if (marker[properties] == value)            return marker;    }}BMapLib.MarkerManager.prototype.findAllInBounds = function (properties, value) {    /// <summary>    /// 查找符合条件的可视范围内标记    /// </summary>    /// <param name="properties">键</param>    /// <param name="value">值</param>    /// <returns type="Array">符合条件的数组</returns>    var bounds = this._map.getBounds();    var finded = new Array;    for (var i = 0; i < this._numMarkers.length; i++) {        var marker = this._numMarkers[i];        if (bounds.containsPoint(marker.getPosition())) {            if (marker[properties] == value) {                finded.push(marker);            }        }    }    return finded;}BMapLib.MarkerManager.prototype.findVisualMarkers = function () {    /// <summary>    /// 查找可视范围内标记    /// </summary>    /// <returns type="Array">可视范围内标记数组</returns>    var bounds = this._map.getBounds();    var finded = new Array;    for (var i = 0; i < this._numMarkers.length; i++) {        var marker = this._numMarkers[i];        if (bounds.containsPoint(marker.getPosition())) {            finded.push(marker);        }    }    return finded;}

注：基于Baidu Map API 1.2

希望有所帮助，谢谢！

[Baidu Map]MarkerManager扩展