【www.gdgbn.com--php函数】

//得到每周的第一天(周一)

function getfirstdateofweek(thedate){
 var firstdateofweek;
 thedate.setdate(thedate.getdate() + 1 - thedate.getday());
 firstdateofweek = thedate;
 return firstdateofweek;
}

//得到每周的最后一天(周日)

function getlastdateofweek(thedate){
 var lastdateofweek;
 thedate.setdate(thedate.getdate() +7 - thedate.getday());
 lastdateofweek = thedate;
 return lastdateofweek;
}

//得到上周的第一天(周一)

function getpreviousfirstdateofweek(thedate){
 var firstdateofweek;
 thedate.setdate(thedate.getdate() - 6 - thedate.getday());
 firstdateofweek = thedate;
 return firstdateofweek;
}

//得到上周的最后一天(周日)

function getpreviouslastdateofweek(thedate){
 var lastdateofweek;
 thedate.setdate(thedate.getdate() - thedate.getday());
 lastdateofweek = thedate;
 return lastdateofweek;
}

 

/---------------------------------------------------
// 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""
//数据库教程中，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;
}

本文来源：http://www.gdgbn.com/jiaocheng/28728/