function getLocation() {
            if (navigator.geolocation) {
                navigator.geolocation.getCurrentPosition(showPosition, showError);
            } else {
                alert("浏览器不支持地理定位。");
            }
        }

        function showError(error) {
            switch (error.code) {
                case error.PERMISSION_DENIED:
                    alert("定位失败,用户拒绝请求地理定位");
                    break;
                case error.POSITION_UNAVAILABLE:
                    alert("定位失败,位置信息是不可用");
                    break;
                case error.TIMEOUT:
                    alert("定位失败,请求获取用户位置超时");
                    break;
                case error.UNKNOWN_ERROR:
                    alert("定位失败,定位系统失效");
                    break;
            }
        }

        function showPosition(position) {
            lat = position.coords.latitude; //纬度 
            lag = position.coords.longitude; //经度 
            alert('纬度:' + lat + ',经度:' + lag);
            
        }