def date_add(sdate='', unit='',i=0)

  sdate[/(\d+)\/(\d+)\/(\d+)\s(\d+):(\d+):(\d+)/]
  iyear = $3.to_i; imonth = $2.to_i; iday = $1.to_i; ihour = $4.to_i; imin = $5.to_i; isec = $6.to_i
  
  case  unit
    when 'days'
      t1 = Time.local(iyear,imonth,iday,ihour,imin,isec)
      t1 += (60 * 60 * 24 * i)
    when 'weeks'
      t1 = Time.local(iyear,imonth,iday,ihour,imin,isec)
      t1 += (60 * 60 * 24 * 7 * i) 
    when 'months'
      imonth += i
      if imonth < 12 then
        t1 = Time.local(iyear,imonth+i,iday,ihour,imin,isec)
      else
        t1 = Time.local(iyear+=1,imonth -12,iday,ihour,imin,isec)
      end
    when 'quarter'
      imonth += 3
      if imonth <= 12 then
        t1 = Time.local(iyear,imonth,iday,ihour,imin,isec)
      else
        t1 = Time.local(iyear+=1,imonth - 12,iday,ihour,imin,isec)
      end    
    when 'years'
      t1 = Time.local(iyear+i,imonth,iday,ihour,imin,isec)
    else
      raise 'not a valid date unit'
  end
  t1
end

date_add("17/03/2008 17:48:00",'months',2)

'VB.NET
Dim NextMonth As Integer
Dim RptYear As Integer
'Determine next month
NextMonth = DatePart(DateInterval.Month, DateAdd(DateInterval.Month, +1, today))
'Determine the year of the next month, in case you are going from Dec to Jan
RptYear = DatePart(DateInterval.Year, DateAdd(DateInterval.Month, +1, today))
'Subtract 1 day from the first day of next month to get this months last day
Return DateAdd(DateInterval.Day, -1, DateValue(NextMonth.ToString & "/1/" & RptYear.ToString))

  <xsl:template name="FormatDate">
    <xsl:param name="DateTime" />
    <!-- new date format 2006-01-14T08:55:22 -->
    <xsl:variable name="mo">
      <xsl:value-of select="substring($DateTime,3,2)" />
    </xsl:variable>
    <xsl:variable name="day">
      <xsl:value-of select="substring($DateTime,5,2)" />
    </xsl:variable>
    <xsl:variable name="year">
      <xsl:value-of select="substring($DateTime,1,2)" />
    </xsl:variable>
    <xsl:variable name="hh">
      <xsl:value-of select="substring($DateTime,7,2)" />
    </xsl:variable>
    <xsl:variable name="mm">
      <xsl:value-of select="substring($DateTime,9,2)" />
    </xsl:variable>
    <xsl:variable name="ss">
      <xsl:value-of select="substring($DateTime,11,2)" />
    </xsl:variable>
    <xsl:if test="(string-length($day) &lt; 2)">
      <xsl:value-of select="0"/>
    </xsl:if>
    <xsl:value-of select="$day"/>
    <xsl:value-of select="'-'"/>
    <xsl:choose>
      <xsl:when test="$mo = '01'">Jan</xsl:when>
      <xsl:when test="$mo = '02'">Feb</xsl:when>
      <xsl:when test="$mo = '03'">Mar</xsl:when>
      <xsl:when test="$mo = '04'">Apr</xsl:when>
      <xsl:when test="$mo = '05'">May</xsl:when>
      <xsl:when test="$mo = '06'">Jun</xsl:when>
      <xsl:when test="$mo = '07'">Jul</xsl:when>
      <xsl:when test="$mo = '08'">Aug</xsl:when>
      <xsl:when test="$mo = '09'">Sep</xsl:when>
      <xsl:when test="$mo = '10'">Oct</xsl:when>
      <xsl:when test="$mo = '11'">Nov</xsl:when>
      <xsl:when test="$mo = '12'">Dec</xsl:when>
    </xsl:choose>
    <xsl:value-of select="'-'"/>

    <xsl:value-of select="$year"/>
    <xsl:value-of select="'T'"/>
    <xsl:value-of select="$hh"/>
    <xsl:value-of select="':'"/>
    <xsl:value-of select="$mm"/>
    <xsl:value-of select="':'"/>
    <xsl:value-of select="$ss"/>
  </xsl:template>

<?php
//Licensed under the GPL v2
//by Evan Walsh of nothingconcept.com
function copyright($site,$year) {
    $current = date(Y);
    if($year == $current) { $eyear = $year; }
    else { $eyear = "$year - $current"; }
    echo "All content &copy; $eyear $site";
}
?>

//+ Jonas Raoni Soares Silva
//@ http://jsfromhell.com/geral/is-date [v1.0]

isDate = function(y, m, d){ //v1.0
        if(typeof y == "string" && m instanceof RegExp && d){
            if(!m.test(y)) return 1;
            y = RegExp["$" + d.y], m = RegExp["$" + d.m], d = RegExp["$" + d.d];
        }
        d = Math.abs(d) || 0, m = Math.abs(m) || 0, y = Math.abs(y) || 0;
        return arguments.length != 3 ? 1 : d < 1 || d > 31 ? 2 : m < 1 || m > 12 ? 3 : /4|6|9|11/.test(m) && d == 31 ? 4
        : m == 2 && (d > ((y = !(y % 4) && (y % 1e2) || !(y % 4e2)) ? 29 : 28)) ? 5 + !!y : 0;
};

<script type="text/javascript">

getDateMsg = function(x){
    return x == 0 ? "Valid Date"
    : x == 1 ? "Invalid date format"
    : x == 2 ? "Invalid day"
    : x == 3 ? "Invalid month"
    : x == 4 ? "In April, June, September and November there's no 31 day"
    : x == 5 ? "February has only 28 days"
    : x == 6 ? "In leap years, February has 29 days": "nothing =]";
};

var x = [
    isDate("22/07/1984", /^([0-9]{1,2})[\/]([0-9]{1,2})[\/]([0-9]{1,4})$/, {d: 1, m: 2, y: 3}),
    isDate("1984-07-22", /^([0-9]{4})-([0-9]{2})-([0-9]{2})$/, {d: 3, m: 2, y: 1}),
    isDate("07-22-1984", /^([0-9]{4})-([0-9]{2})-([0-9]{2})$/, {d: 3, m: 2, y: 1}),
    isDate(2000, 1, 32),
    isDate(2000, 0, 1),
    isDate(2000, 4, 31),
    isDate(2001, 2, 29),
    isDate(2004, 2, 30)
];

for(var i = -1, l = x.length; ++i < l; document.write(getDateMsg(x[i]), "<br />"));

</script>

isDate(y: Integer, m: Integer, d: Integer): Integer
    Checks a date and returns 0 if it's valid or one of the error codes bellow.
    y year
    m month
    d day

	
isDate(date: String, matcher: RegExp, map: Object): Integer
    Checks a date and returns 0 if it's valid or one of the error codes bellow.
    date date in a string form
    matcher regular expression responsible to find and store the day, month and year
    			
    map object containing the position where each date component is localized inside the regular expression. Its format is the following: {d: positionOfTheDay, m: positionOfTheMonth, y: positionOfTheYear}								
Return codes
    * 0 = Valid date
    * 1 = Date format invalid (regular expression failed or amount of arguments != 3)
    * 2 = Day isn't between 1 and 31
    * 3 = Month isn't between 1 and 12
    * 4 = On April, June, September and November there isn't the day 31
    * 5 = On February the month has only 28 days
    * 6 = Leap year, February has only 29 days

/*
### begin_: file metadata
    ### <region-file_info>
    ### main:
    ###   - name : cfDateTime.js
    ###     desc : |
    ###         Simple date operations in jscript.
    ###         This file is for use with windows scripting host.
    ###     date : created="Thu 2005-12-01 11:57:38"
    ###     last : lastmod="Thu 2005-12-01 12:18:57"
    ###     lang : jscript
    ###     tags : jscript javascript date time now month hour year cfDateTime
    ### </region-file_info>
    */

/// begin_: declare and init variables
    var today       = new Date();
    var strYear     = today.getFullYear();
    var iMonth      = today.getMonth() + 1; // +1, we do NOT want zero-based month index
    var iQuarter    = Math.ceil((iMonth / 12) * 4);
    var iDay        = today.getDate();
    var strDateOut  = "";

/// begin_: leading zeropad single-digit numbers
    iMonth = (iMonth < 10)? "0" + iMonth : iMonth;
    iDay = (iDay < 10)? "0" + iDay : iDay;

/// begin_: display output
    strDateOut = strYear+"-"+ iMonth +"-"+iDay + " ";
    WScript.Echo (strDateOut);

### begin_: file metadata
    ### <region-file_info>
    ### main:
    ###   - name : DateTime.pl
    ###     desc : DateTime: generic date and time script in perl
    ###     date : created="Thu 2005-12-01 10:04:52"
    ###     last : lastmod="Thu 2005-12-01 10:04:59"
    ### </region-file_info>

### begin_: initialize perl (optional)
    use strict;
    use warnings;

### begin_: initialize DateTime values
    my %dttime = ();
    my ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) = localtime(time);

### begin_: initialize DateTime number formats
    $dttime{year }  = sprintf "%04d",($year + 1900);  ## four digits to specify the year
    $dttime{mon  }  = sprintf "%02d",($mon + 1);      ## zeropad months
    $dttime{mday }  = sprintf "%02d",$mday;           ## zeropad day of the month
    $dttime{wday }  = sprintf "%02d",$wday + 1;       ## zeropad day of week; sunday = 1;
    $dttime{yday }  = sprintf "%02d",$yday;           ## zeropad nth day of the year
    $dttime{hour }  = sprintf "%02d",$hour;           ## zeropad hour
    $dttime{min  }  = sprintf "%02d",$min;            ## zeropad minutes
    $dttime{sec  }  = sprintf "%02d",$sec;            ## zeropad seconds
    $dttime{isdst}  = $isdst;

### begin_: xnpDate print iso8601 version date
    print "$dttime{year}-$dttime{mon}-$dttime{mday}\n";

### begin_: xnpNow show system time
    print "$dttime{year}-$dttime{mon}-$dttime{mday} $dttime{hour}:$dttime{min}:$dttime{sec} \n";

// ---------------------------------------------------------------------------|
// qryHowOld                                                                  |
// Description: How old someone is in the format:                             |
// XXX Years XX Months X Weeks X Days                                         |
// Birth Date could be specified like Date.UTC(2002,8,16,17,42,0)             |
//                                                                            |
// Arguments:                                                                 |
//    varAsOfDate: as of date                                                 |
//    varBirthDate: birth date                                                |
//                                                                            |
function qryHowOld(varAsOfDate, varBirthDate)
   {
   var dtAsOfDate;
   var dtBirth;
   var dtAnniversary;
   var intSpan;
   var intYears;
   var intMonths;
   var intWeeks;
   var intDays;
   var intHours;
   var intMinutes;
   var intSeconds;
   var strHowOld;

   // get born date
   dtBirth = new Date(varBirthDate);
   
   // get as of date
   dtAsOfDate = new Date(varAsOfDate);

   // if as of date is on or after born date
   if ( dtAsOfDate >= dtBirth )
      {

      // get time span between as of time and birth time
      intSpan = ( dtAsOfDate.getUTCHours() * 3600000 +
                  dtAsOfDate.getUTCMinutes() * 60000 +
                  dtAsOfDate.getUTCSeconds() * 1000    ) -
                ( dtBirth.getUTCHours() * 3600000 +
                  dtBirth.getUTCMinutes() * 60000 +
                  dtBirth.getUTCSeconds() * 1000       )

      // start at as of date and look backwards for anniversary 

      // if as of day (date) is after birth day (date) or
      //    as of day (date) is birth day (date) and
      //    as of time is on or after birth time
      if ( dtAsOfDate.getUTCDate() > dtBirth.getUTCDate() ||
           ( dtAsOfDate.getUTCDate() == dtBirth.getUTCDate() && intSpan >= 0 ) )
         {

         // most recent day (date) anniversary is in as of month
         dtAnniversary = 
            new Date( Date.UTC( dtAsOfDate.getUTCFullYear(),
                                dtAsOfDate.getUTCMonth(),
                                dtBirth.getUTCDate(),
                                dtBirth.getUTCHours(),
                                dtBirth.getUTCMinutes(),
                                dtBirth.getUTCSeconds() ) );

         }

      // if as of day (date) is before birth day (date) or
      //    as of day (date) is birth day (date) and
      //    as of time is before birth time
      else
         {

         // most recent day (date) anniversary is in month before as of month
         dtAnniversary = 
            new Date( Date.UTC( dtAsOfDate.getUTCFullYear(),
                                dtAsOfDate.getUTCMonth() - 1,
                                dtBirth.getUTCDate(),
                                dtBirth.getUTCHours(),
                                dtBirth.getUTCMinutes(),
                                dtBirth.getUTCSeconds() ) );

         // get previous month
         intMonths = dtAsOfDate.getUTCMonth() - 1;
         if ( intMonths == -1 )
            intMonths = 11;

         // while month is not what it is supposed to be (it will be higher)
         while ( dtAnniversary.getUTCMonth() != intMonths )

            // move back one day
            dtAnniversary.setUTCDate( dtAnniversary.getUTCDate() - 1 );

         }

      // if anniversary month is on or after birth month
      if ( dtAnniversary.getUTCMonth() >= dtBirth.getUTCMonth() )
         {

         // months elapsed is anniversary month - birth month
         intMonths = dtAnniversary.getUTCMonth() - dtBirth.getUTCMonth();

         // years elapsed is anniversary year - birth year
         intYears = dtAnniversary.getUTCFullYear() - dtBirth.getUTCFullYear();

         }

      // if birth month is after anniversary month
      else
         {

         // months elapsed is months left in birth year + anniversary month
         intMonths = (11 - dtBirth.getUTCMonth()) + dtAnniversary.getUTCMonth() + 1;

         // years elapsed is year before anniversary year - birth year
         intYears = (dtAnniversary.getUTCFullYear() - 1) - dtBirth.getUTCFullYear();

         }

      // to calculate weeks, days, hours, minutes and seconds
      // we can take the difference from anniversary date and as of date

      // get time span between two dates in milliseconds
      intSpan = dtAsOfDate - dtAnniversary;

      // get number of weeks
      intWeeks = Math.floor(intSpan / 604800000);

      // subtract weeks from time span
      intSpan = intSpan - (intWeeks * 604800000);
      
      // get number of days
      intDays = Math.floor(intSpan / 86400000);

      // subtract days from time span
      intSpan = intSpan - (intDays * 86400000);

      // get number of hours
      intHours = Math.floor(intSpan / 3600000);
    
      // subtract hours from time span
      intSpan = intSpan - (intHours * 3600000);

      // get number of minutes
      intMinutes = Math.floor(intSpan / 60000);

      // subtract minutes from time span
      intSpan = intSpan - (intMinutes * 60000);

      // get number of seconds
      intSeconds = Math.floor(intSpan / 1000);

      // create output string     
      if ( intYears > 0 )
         if ( intYears > 1 )
            strHowOld = intYears.toString() + ' Years';
         else
            strHowOld = intYears.toString() + ' Year';
      else
         strHowOld = '';

      if ( intMonths > 0 )
         if ( intMonths > 1 )
            strHowOld = strHowOld + ' ' + intMonths.toString() + ' Months';
         else
            strHowOld = strHowOld + ' ' + intMonths.toString() + ' Month';
           
      if ( intWeeks > 0 )
         if ( intWeeks > 1 )
            strHowOld = strHowOld + ' ' + intWeeks.toString() + ' Weeks';
         else
            strHowOld = strHowOld + ' ' + intWeeks.toString() + ' Week';

      if ( intDays > 0 )
         if ( intDays > 1 )
            strHowOld = strHowOld + ' ' + intDays.toString() + ' Days';
         else
            strHowOld = strHowOld + ' ' + intDays.toString() + ' Day';

      if ( intHours > 0 )
         if ( intHours > 1 )
            strHowOld = strHowOld + ' ' + intHours.toString() + ' Hours';
         else
            strHowOld = strHowOld + ' ' + intHours.toString() + ' Hour';
 
      if ( intMinutes > 0 )
         if ( intMinutes > 1 )
            strHowOld = strHowOld + ' ' + intMinutes.toString() + ' Minutes';
         else
            strHowOld = strHowOld + ' ' + intMinutes.toString() + ' Minute';

      if ( intSeconds > 0 )
         if ( intSeconds > 1 )
            strHowOld = strHowOld + ' ' + intSeconds.toString() + ' Seconds';
         else
            strHowOld = strHowOld + ' ' + intSeconds.toString() + ' Second';

      }
   else
      strHowOld = 'Not Born Yet'

   // return string representation
   return strHowOld
   }   
//                                                                            |
// qryHowOld                                                                  |
// ---------------------------------------------------------------------------|