function TimeCom( dateValue )
{
    var newCom = new Date( dateValue );
    this.year = newCom.getFullYear();
    //var xx=new Date();
    //alert(xx.getFullYear());
    this.month = newCom.getMonth()+1;
    this.day = newCom.getDate();
    this.hour = newCom.getHours();
    this.minute = newCom.getMinutes();
    this.second = newCom.getSeconds();
    this.msecond = newCom.getMilliseconds();
    this.week = newCom.getDay();
}

function DateDiff(interval,date1,date2)
{
    var TimeCom1 = new TimeCom(date1);
    var TimeCom2 = new TimeCom(date2);
    var result;
    switch(String(interval).toLowerCase())
    {
        case "y":
        case "year":
        result = TimeCom1.year-TimeCom2.year;
        break;
        case "n":
        case "month":
        result = (TimeCom1.year-TimeCom2.year)*12+(TimeCom1.month-TimeCom2.month);
        break;
        case "d":
        case "day":
        result = Math.round((Date.UTC(TimeCom1.year,TimeCom1.month-1,TimeCom1.day)-Date.UTC(TimeCom2.year,TimeCom2.month-1,TimeCom2.day))/(1000*60*60*24));
        break;
        case "h":
        case "hour":
        result = Math.round((Date.UTC(TimeCom1.year,TimeCom1.month-1,TimeCom1.day,TimeCom1.hour)-Date.UTC(TimeCom2.year,TimeCom2.month-1,TimeCom2.day,TimeCom2.hour))/(1000*60*60));
        break;
        case "m":
        case "minute":
        result = Math.round((Date.UTC(TimeCom1.year,TimeCom1.month-1,TimeCom1.day,TimeCom1.hour,TimeCom1.minute)-Date.UTC(TimeCom2.year,TimeCom2.month-1,TimeCom2.day,TimeCom2.hour,TimeCom2.minute))/(1000*60));
        break;
        case "s":
        case "second":
        result = Math.round((Date.UTC(TimeCom1.year,TimeCom1.month-1,TimeCom1.day,TimeCom1.hour,TimeCom1.minute,TimeCom1.second)-Date.UTC(TimeCom2.year,TimeCom2.month-1,TimeCom2.day,TimeCom2.hour,TimeCom2.minute,TimeCom2.second))/1000);
        break;
        case "ms":
        case "msecond":
        result = Date.UTC(TimeCom1.year,TimeCom1.month-1,TimeCom1.day,TimeCom1.hour,TimeCom1.minute,TimeCom1.second,TimeCom1.msecond)-Date.UTC(TimeCom2.year,TimeCom2.month-1,TimeCom2.day,TimeCom2.hour,TimeCom2.minute,TimeCom2.second,TimeCom1.msecond);
        break;
        case "w":
        case "week":
        result = Math.round((Date.UTC(TimeCom1.year,TimeCom1.month-1,TimeCom1.day)-Date.UTC(TimeCom2.year,TimeCom2.month-1,TimeCom2.day))/(1000*60*60*24)) % 7;
        break;
        default:
        result = "invalid";
    }
    return(result);
}

function DateAdd(interval, num, dateValue)
{
    var newCom = new TimeCom(dateValue);
    switch(String(interval).toLowerCase())
    {
        case "y": case "year": newCom.year += num; break;
        case "n": case "month": newCom.month += num; break;
        case "d": case "day": newCom.day += num; break;
        case "h": case "hour": newCom.hour += num; break;
        case "m": case "minute": newCom.minute += num; break;
        case "s": case "second": newCom.second += num; break;
        case "ms": case "msecond": newCom.msecond += num; break;
        case "w": case "week": newCom.day += num*7; break;
        default: return("invalid");
    }
    //alert(newCom.year);
    if(newCom.day<0)
    {
        newCom.day=0;
    }
    var now = newCom.year+"/"+newCom.month+"/"+newCom.day+" "+newCom.hour+":"+newCom.minute+":"+newCom.second;
    return(new Date(now));
}