function isLeapYear(year)
{
 leap = ((0==(year % 4)) && ((0 != (year % 100)) || (0 == (year % 400))));
 if (leap) return 29
 else return 28
}


function weeknr(year,month,day,format)
{
feb = isLeapYear(year)
month_array = new Array(31,feb,31,30,31,30,31,31,30,31,30,31);
first_day = new Date(year,0,1);
end_day = new Date(year,month,day);

end_date = end_day.getDay();
begin_first_day = first_day.getDay();

if (format == 1)
{
 end_date--;
 if (end_date == -1) end_date = 6;
 begin_first_day--;
 if (begin_first_day == -1) begin_first_day = 6; 
}

end_date = 6 - end_date;
between = 0;
for(i=0;i<=(end_day.getMonth()-1);i++)
{
 between = between + month_array[i];
}
between += begin_first_day + day + end_date;

if ((between % 7) == 0)
{
 week = (between / 7);
}
else
{
 week = Math.floor(between/7);
}
if (week == 53) week = 1
return week
}

var_date = new Date()
week= weeknr(var_date.getFullYear(),var_date.getMonth(),var_date.getDate(),1);


document.write(week);