一个格式化日期和时间的JavaScript类库

　　原文地址：http://www.cnblogs.com/zhangpengshou/archive/2012/07/19/2599053.html

　　结合meizz的代码做了适当调整。

Date.prototype.Format = function (fmt) {
    var that = this;
    var postfix = false;
    var o = {
        "M+": this.getMonth() + 1, //month
        "d+": this.getDate(), //day
        "h+": function () {
            return postfix ? (that.getHours() % 12 == 0 ? 12 : that.getHours() % 12) : that.getHours();
        }, //hour
        "m+": this.getMinutes(), //minute
        "s+": this.getSeconds(), //second
        "q+": Math.floor((this.getMonth() + 3) / 3), //quarter
        "S": this.getMilliseconds() //millisecond
    };
    if (/(y+)/.test(fmt)) fmt = fmt.replace(RegExp.$1, (this.getFullYear() + "").substr(4 - RegExp.$1.length));
    for (var k in o) {
        if (new RegExp("(" + k + ")").test(fmt)) {
            if (RegExp.$1.length == 1 && RegExp.$1 == "h") postfix = true;
            var val = typeof (o[k]) == "function" ? o[k].apply(this) : o[k];
            fmt = fmt.replace(RegExp.$1, (RegExp.$1.length == 1) ? (val) : (("00" + val).substr(("" + val).length)));

        }
    }
    return fmt + (postfix ? ((this.getHours() < 12) ? " AM" : " PM") : "");
}

// following are testing code
var Ld = "26-09-2014";
var Lt = "13:15:23";

var arrDateParts = Ld.split("-");
if (arrDateParts.length == 3) {
    var dayNum = arrDateParts[0];
    var monthNum = arrDateParts[1];
    var yearNum = arrDateParts[2];
    var D = new Date(monthNum.concat("/", dayNum, "/", yearNum, ' ', Lt));
    console.info(D.Format("M/dd/yyyy h:mm:ss"));
}

　　以上代码可根据所提供的格式字符串以及时间来判断是否需要添加AM/PM后缀。