JS将毫秒时间戳转换成合适的时间字符串

function convertTimestampToString(timestamp)
{
    var now = new Date();
    var yy = now.getFullYear();      //年
    var mm = now.getMonth() + 1;     //月
    var dd = now.getDate();          //日
    var hh = now.getHours();         //时
    var ii = now.getMinutes();       //分
    var ss = now.getSeconds();       //秒

    var nowTimestamp = now.getTime();

    var d = new Date(timestamp);    //根据时间戳生成的时间对象
    var tyear = d.getFullYear();
    var tmonth = d.getMonth() + 1;
    var tday = d.getDate();
    var week = d.getDay();
    var thour = d.getHours();
    var tminute = d.getMinutes();
    var tseconds = d.getSeconds();

    var diffTime = nowTimestamp - timestamp;
    if (tyear < yy) {
        if (tmonth < 10) {
            tmonth = '0' + tmonth;
        }
        if (tday < 10) {
            tday = '0' + tday;
        }
        return tyear+'-'+tmonth+'-'+tday;
    } else if(tmonth < mm && (diffTime > 604800000)) {
        var str='';
        if (tmonth < 10) {
            str += '0' + tmonth;
        } else {
            str += tmonth;
        }
        if (dd < 10) {
            str += '-0' + dd;
        } else {
            str += '-' + dd;
        }

        return str;
    } else {
        if (tday != dd) {
            var day = '';
            switch (week) {
                case 1 : day="星期一";break;
                case 2 : day="星期二";break;
                case 3 : day="星期三";break;
                case 4 : day="星期四";break;
                case 5 : day="星期五";break;
                case 6 : day="星期六";break;
                case 7 : day="星期日";break;
            }
            return day;
        } else {
            var str = "";
            if (thour > 12) {
                var hour = thour - 12;
                str = "下午";
            } else {
                var hour = thour;
                str = '上午';
            }

            if (hour < 10) {
                hour = '0' + hour;
            }
            if (tminute < 10) {
                tminute = '0' + tminute;
            }

            return str + hour+':'+tminute;

        }
    }
}