js获取当前日期和前两天日期

<script type="text/javascript">

getBeforeDate =function(){
    var date = date || new Date(), timestamp, 
    newDate;
    if(!(date instanceof Date)){
        date = new Date(date.replace(/-/g, '/'));//格式化日期
    }
    timestamp = date.getTime();//获取时间戳毫秒
    newDate = new Date(timestamp - 2* 24 * 3600 * 1000);//前俩天时间戳
    var month = newDate.getMonth() + 1;//当前月份
    month = month.toString().length == 1 ? '0' + month : month; //月份格式
    var nowday = date.getDate().toString().length == 1 ? '0' + date.getDate() :date.getDate();//当前日期格式

    var nowMonth = date.getMonth() + 1;//前两天月份
    nowMonth = nowMonth.toString().length == 1 ? '0' + nowMonth : nowMonth; //前两天月份格式
    var day = newDate.getDate().toString().length == 1 ? '0' + newDate.getDate() :newDate.getDate();//前两天日期格式
    
    return [newDate.getFullYear(), month, day].join('-')+'&'+[date.getFullYear(), nowMonth, nowday].join('-');
}
</script>

//来源于网路，但不知道链接，侵删，只用于个人学习