Date操作方法收集（转载）

Js获取当前日期时间及其它操作
var myDate = new Date();
myDate.getYear();        //获取当前年份(2位)
myDate.getFullYear();    //获取完整的年份(4位,1970-????)
myDate.getMonth();       //获取当前月份(0-11,0代表1月)
myDate.getDate();        //获取当前日(1-31)
myDate.getDay();         //获取当前星期X(0-6,0代表星期天)
myDate.getTime();        //获取当前时间(从1970.1.1开始的毫秒数)
myDate.getHours();       //获取当前小时数(0-23)
myDate.getMinutes();     //获取当前分钟数(0-59)
myDate.getSeconds();     //获取当前秒数(0-59)
myDate.getMilliseconds();    //获取当前毫秒数(0-999)
myDate.toLocaleDateString();     //获取当前日期
var mytime=myDate.toLocaleTimeString();     //获取当前时间
myDate.toLocaleString( );        //获取日期与时间
日期时间脚本库方法列表
Date.prototype.isLeapYear 判断闰年
Date.prototype.Format 日期格式化
Date.prototype.DateAdd 日期计算
Date.prototype.DateDiff 比较日期差
Date.prototype.toString 日期转字符串
Date.prototype.toArray 日期分割为数组
Date.prototype.DatePart 取日期的部分信息
Date.prototype.MaxDayOfDate 取日期所在月的最大天数
Date.prototype.WeekNumOfYear 判断日期所在年的第几周
StringToDate 字符串转日期型
IsValidDate 验证日期有效性
CheckDateTime 完整日期时间检查
daysBetween 日期天数差
js代码：
//--------------------------------------------------- 
// 判断闰年 
//--------------------------------------------------- 
Date.prototype.isLeapYear = function()  
{  
    return (0==this.getYear()%4&&((this.getYear()%100!=0)||(this.getYear()%400==0)));  
}  
//--------------------------------------------------- 
// 日期格式化 
// 格式 YYYY/yyyy/YY/yy 表示年份 
// MM/M 月份 
// W/w 星期 
// dd/DD/d/D 日期 
// hh/HH/h/H 时间 
// mm/m 分钟 
// ss/SS/s/S 秒 
//--------------------------------------------------- 
Date.prototype.Format = function(formatStr)  
{  
    var str = formatStr;  
    var Week = ['日','一','二','三','四','五','六'];
    str=str.replace(/yyyy|YYYY/,this.getFullYear());  
    str=str.replace(/yy|YY/,(this.getYear() % 100)>9?(this.getYear() % 100).toString():'0' + (this.getYear() % 100));  
    str=str.replace(/MM/,this.getMonth()>9?this.getMonth().toString():'0' + this.getMonth());  
    str=str.replace(/M/g,this.getMonth());  
    str=str.replace(/w|W/g,Week[this.getDay()]);  
    str=str.replace(/dd|DD/,this.getDate()>9?this.getDate().toString():'0' + this.getDate());  
    str=str.replace(/d|D/g,this.getDate());  
    str=str.replace(/hh|HH/,this.getHours()>9?this.getHours().toString():'0' + this.getHours());  
    str=str.replace(/h|H/g,this.getHours());  
    str=str.replace(/mm/,this.getMinutes()>9?this.getMinutes().toString():'0' + this.getMinutes());  
    str=str.replace(/m/g,this.getMinutes());  
    str=str.replace(/ss|SS/,this.getSeconds()>9?this.getSeconds().toString():'0' + this.getSeconds());  
    str=str.replace(/s|S/g,this.getSeconds());  
    return str;  
}  
//+--------------------------------------------------- 
//|求两个时间的天数差 日期格式为 YYYY-MM-dd  
//+--------------------------------------------------- 
function daysBetween(DateOne,DateTwo)
{  
    var OneMonth = DateOne.substring(5,DateOne.lastIndexOf ('-'));
    var OneDay = DateOne.substring(DateOne.length,DateOne.lastIndexOf ('-')+1);
    var OneYear = DateOne.substring(0,DateOne.indexOf ('-'));
    var TwoMonth = DateTwo.substring(5,DateTwo.lastIndexOf ('-'));
    var TwoDay = DateTwo.substring(DateTwo.length,DateTwo.lastIndexOf ('-')+1);
    var TwoYear = DateTwo.substring(0,DateTwo.indexOf ('-'));
    var cha=((Date.parse(OneMonth+'/'+OneDay+'/'+OneYear)- Date.parse(TwoMonth+'/'+TwoDay+'/'+TwoYear))/86400000);  
    return Math.abs(cha);
}
//+--------------------------------------------------- 
//| 日期计算 
//+--------------------------------------------------- 
Date.prototype.DateAdd = function(strInterval, Number) {  
    var dtTmp = this;
    switch (strInterval) {  
        case 's' :return new Date(Date.parse(dtTmp) + (1000 * Number));
        case 'n' :return new Date(Date.parse(dtTmp) + (60000 * Number));
        case 'h' :return new Date(Date.parse(dtTmp) + (3600000 * Number));
        case 'd' :return new Date(Date.parse(dtTmp) + (86400000 * Number));
        case 'w' :return new Date(Date.parse(dtTmp) + ((86400000 * 7) * Number));
        case 'q' :return new Date(dtTmp.getFullYear(), (dtTmp.getMonth()) + Number*3, dtTmp.getDate(), dtTmp.getHours(), dtTmp.getMinutes(), dtTmp.getSeconds());
        case 'm' :return new Date(dtTmp.getFullYear(), (dtTmp.getMonth()) + Number, dtTmp.getDate(), dtTmp.getHours(), dtTmp.getMinutes(), dtTmp.getSeconds());
        case 'y' :return new Date((dtTmp.getFullYear() + Number), dtTmp.getMonth(), dtTmp.getDate(), dtTmp.getHours(), dtTmp.getMinutes(), dtTmp.getSeconds());
    }
}
//+--------------------------------------------------- 
//|比较日期差 dtEnd 格式为日期型或者 有效日期格式字符串 
//+--------------------------------------------------- 
Date.prototype.DateDiff = function(strInterval, dtEnd) {  
    var dtStart = this;
    if (typeof dtEnd == 'string' )//如果是字符串转换为日期型
    {  
        dtEnd = StringToDate(dtEnd);
    }
    switch (strInterval) {  
        case 's' :return parseInt((dtEnd - dtStart) / 1000);
        case 'n' :return parseInt((dtEnd - dtStart) / 60000);
        case 'h' :return parseInt((dtEnd - dtStart) / 3600000);
        case 'd' :return parseInt((dtEnd - dtStart) / 86400000);
        case 'w' :return parseInt((dtEnd - dtStart) / (86400000 * 7));
        case 'm' :return (dtEnd.getMonth()+1)+((dtEnd.getFullYear()-dtStart.getFullYear())*12) - (dtStart.getMonth()+1);
        case 'y' :return dtEnd.getFullYear() - dtStart.getFullYear();
    }
}
//+--------------------------------------------------- 
//| 日期输出字符串，重载了系统的toString方法 
//+--------------------------------------------------- 
Date.prototype.toString = function(showWeek)
{  
    var myDate= this;
    var str = myDate.toLocaleDateString();
    if (showWeek)
    {  
        var Week = ['日','一','二','三','四','五','六'];
        str += ' 星期' + Week[myDate.getDay()];
    }
    return str;
}
//+--------------------------------------------------- 
//| 日期合法性验证 
//| 格式为：YYYY-MM-DD或YYYY/MM/DD 
//+--------------------------------------------------- 
function IsValidDate(DateStr)  
{  
    var sDate=DateStr.replace(/(^\s+|\s+$)/g,''); //去两边空格;  
    if(sDate=='') return true;  
    //如果格式满足YYYY-(/)MM-(/)DD或YYYY-(/)M-(/)DD或YYYY-(/)M-(/)D或YYYY-(/)MM-(/)D就替换为''  
    //数据库中，合法日期可以是:YYYY-MM/DD(2003-3/21),数据库会自动转换为YYYY-MM-DD格式  
    var s = sDate.replace(/[\d]{ 4,4 }[\-/]{ 1 }[\d]{ 1,2 }[\-/]{ 1 }[\d]{ 1,2 }/g,'');  
    if (s=='') //说明格式满足YYYY-MM-DD或YYYY-M-DD或YYYY-M-D或YYYY-MM-D  
    {  
        var t=new Date(sDate.replace(/\-/g,'/'));  
        var ar = sDate.split(/[-/:]/);  
        if(ar[0] != t.getYear() || ar[1] != t.getMonth()+1 || ar[2] != t.getDate())  
        {  
            //alert('错误的日期格式！格式为：YYYY-MM-DD或YYYY/MM/DD。注意闰年。');  
            return false;  
        }  
    }  
    else  
    {  
        //alert('错误的日期格式！格式为：YYYY-MM-DD或YYYY/MM/DD。注意闰年。');  
        return false;  
    }  
    return true;  
}  
//+--------------------------------------------------- 
//| 日期时间检查 
//| 格式为：YYYY-MM-DD HH:MM:SS 
//+--------------------------------------------------- 
function CheckDateTime(str)
{  
    var reg = /^(\d+)-(\d{ 1,2 })-(\d{ 1,2 }) (\d{ 1,2 }):(\d{ 1,2 }):(\d{ 1,2 })$/;  
    var r = str.match(reg);  
    if(r==null)return false;  
    r[2]=r[2]-1;  
    var d= new Date(r[1],r[2],r[3],r[4],r[5],r[6]);  
    if(d.getFullYear()!=r[1])return false;  
    if(d.getMonth()!=r[2])return false;  
    if(d.getDate()!=r[3])return false;  
    if(d.getHours()!=r[4])return false;  
    if(d.getMinutes()!=r[5])return false;  
    if(d.getSeconds()!=r[6])return false;  
    return true;  
}  
//+--------------------------------------------------- 
//| 把日期分割成数组 
//+--------------------------------------------------- 
Date.prototype.toArray = function()
{  
    var myDate = this;
    var myArray = Array();
    myArray[0] = myDate.getFullYear();
    myArray[1] = myDate.getMonth();
    myArray[2] = myDate.getDate();
    myArray[3] = myDate.getHours();
    myArray[4] = myDate.getMinutes();
    myArray[5] = myDate.getSeconds();
    return myArray;
}
//+--------------------------------------------------- 
//| 取得日期数据信息 
//| 参数 interval 表示数据类型 
//| y 年 m月 d日 w星期 ww周 h时 n分 s秒 
//+--------------------------------------------------- 
Date.prototype.DatePart = function(interval)
{  
    var myDate = this;
    var partStr='';
    var Week = ['日','一','二','三','四','五','六'];
    switch (interval)
    {  
        case 'y' :partStr = myDate.getFullYear();break;
        case 'm' :partStr = myDate.getMonth()+1;break;
        case 'd' :partStr = myDate.getDate();break;
        case 'w' :partStr = Week[myDate.getDay()];break;
        case 'ww' :partStr = myDate.WeekNumOfYear();break;
        case 'h' :partStr = myDate.getHours();break;
        case 'n' :partStr = myDate.getMinutes();break;
        case 's' :partStr = myDate.getSeconds();break;
    }
    return partStr;
}
//+--------------------------------------------------- 
//| 取得当前日期所在月的最大天数 
//+--------------------------------------------------- 
Date.prototype.MaxDayOfDate = function()
{  
    var myDate = this;
    var ary = myDate.toArray();
    var date1 = (new Date(ary[0],ary[1]+1,1));
    var date2 = date1.dateAdd(1,'m',1);
    var result = dateDiff(date1.Format('yyyy-MM-dd'),date2.Format('yyyy-MM-dd'));
    return result;
}
//+--------------------------------------------------- 
//| 取得当前日期所在周是一年中的第几周 
//+--------------------------------------------------- 
Date.prototype.WeekNumOfYear = function()
{  
    var myDate = this;
    var ary = myDate.toArray();
    var year = ary[0];
    var month = ary[1]+1;
    var day = ary[2];
    document.write('< script language=VBScript\> \n');
    document.write('myDate = DateValue(''+month+'-'+day+'-'+year+'') \n');
    document.write('result = DatePart('ww', myDate) \n');
    document.write(' \n');
    return result;
}
//+--------------------------------------------------- 
//| 字符串转成日期类型  
//| 格式 MM/dd/YYYY MM-dd-YYYY YYYY/MM/dd YYYY-MM-dd 
//+--------------------------------------------------- 
function StringToDate(DateStr)
{  
    var converted = Date.parse(DateStr);
    var myDate = new Date(converted);
    if (isNaN(myDate))
    {  
        //var delimCahar = DateStr.indexOf('/')!=-1?'/':'-';
        var arys= DateStr.split('-');
        myDate = new Date(arys[0],--arys[1],arys[2]);
    }
    return myDate;
}

js比较2个时间大小

var x=new Date();
 x.setFullYear(2100,0,14);
var today = new Date();
 if (x>today){
   alert("Today is before 14th January 2100");
   }else{
   alert("Today is after 14th January 2100");
   }