javascript时间函数的运用：根据开始时间和时间差来计算截至时间的解决方案

//计算时间;
function getTimes(fromTime, hours) {
    fromTime = fromTime.replace(new RegExp("-", "gm"), "/");
    var startDate = (new Date(fromTime)).getTime();
    var d3 = startDate - hours * 3600 * 1000;
    var endDate = timestampToTime(d3);
    return endDate;
}

//将时间戳转换成正常时间格式;
function timestampToTime(timestamp) {
    var date = new Date(timestamp);
    var Y = date.getFullYear() + '-';
    var M = timeAdd0((date.getMonth() + 1).toString()) + '-';
    var D = timeAdd0(date.getDate().toString()) + ' ';
    var h = timeAdd0(date.getHours().toString()) + ':';
    var m = timeAdd0(date.getMinutes().toString()) + ':';
    var s = timeAdd0(date.getSeconds().toString());
    return Y + M + D + h + m + s;
}

//补齐十位数;
function timeAdd0(str) {
    if (str.length <= 1) {
        str = '0' + str;
    }
    return str
}