Method bind

src/common/overlay/levelRenderer/Eventful.js:84–102

* @function LevelRenderer.Eventful.prototype.bind * @description 绑定事件。 * @param {string} event - 事件名。 * @param {boolean} handler - 响应函数。 * @param {Object} context - context。 * @returns {LevelRenderer.Eventful} this

(event, handler, context)

     * @returns {LevelRenderer.Eventful} this
     */
    bind(event, handler, context) {
        var _h = this._handlers;

        if (!handler || !event) {
            return this;
        }

        if (!_h[event]) {
            _h[event] = [];
        }

        _h[event].push({
            h: handler,
            one: false,
            ctx: context || this
        });

        return this;
    }


    /**