js中ajax的异步性

function ajaxGetEvents(calendarView, time) {
    var year = time.getFullYear();
    var month = time.getMonth() + 1 < 10 ? "0" + (time.getMonth() + 1) : time.getMonth() + 1;
    var day = time.getDate() < 10 ? "0" + time.getDate() : time.getDate();
    var timeStr = year + "-" + month + "-" + day;
    var ajaxData = {
        search_monthNum : timeStr;
    };
    var ajaxUrl = localStorage.getItem("globalUrl") + ‘trip/sheduleInfo!monthList.action‘;
    var eventsData;
    $.ajax( {
        type : ‘post‘,
        dataType : ‘json‘,
        url : ajaxUrl,
        data : ajaxData,
        async: false,//此处设置ajax为同步请求
        success : function(data) {
            if (data.retCode == ‘1‘) {
                eventsData = data.returnData;
            } else {
                console.log(data.message);
            }
        },
        error : function() {
            console.log(‘ajax error in calendar.js‘);
        }
    });
    return eventsData;
}

$(function(){
    var lat, lng;
    getCurrPosition();
    $(‘#position‘).html("lat = " + lat + ‘  lng = ‘ + lng);

    function getCurrPosition(){
        if(navigator.geolocation){
            navigator.geolocation.getCurrentPosition(getPositionSuccess, getPositionError);
        }else{
            alert("您的浏览器不支持Geolocation!");
        }
    }
    function getPositionSuccess(position) {
        lat = position.coords.latitude;
        lng = position.coords.longitude; 
    }
    function getPositionError(error){
        switch (error.code) {
            case error.TIMEOUT:
                alert("连接超时，请重试");
                break;
            case error.PERMISSION_DENIED:
                alert("您拒绝了使用位置共享服务，查询已取消");
                break;
            case error.POSITION_UNAVAILABLE:
                alert("位置信息不可用");
                break;
        }
    }
});