var calendarUrl = '?date='; 
var calendarYear = 2010; 
var calendarMonth = 6; 
var calendarViewId = 'calendar'; 
var calendarNavId = 'month'; 
function setPreviousYear()
{
    calendarYear--;
    displayCalendar();
}
function setPreviousMonth()
{
    if (calendarMonth <= 0) {
        calendarMonth = 11;
        calendarYear--;
    } else {
        calendarMonth--;
    }
    displayCalendar();
}
function setNextMonth()
{
    if (calendarMonth >= 11) {
        calendarMonth = 0;
        calendarYear++;
    } else {
        calendarMonth++;
    }
    displayCalendar();
}
function setNextYear()
{
    calendarYear++;
    displayCalendar();
}
function displayCalendar()
{
    // отрисовка календаря
    var month = calendarMonth;
    var year = calendarYear;
    var htmlCod = '<table width="180" cellpadding="0" cellspacing="0">';
    htmlCod += '<tr align="center">';
    htmlCod += '<td>' + arrWeekDays[0] + '</td>';
    htmlCod += '<td>' + arrWeekDays[1] + '</td>';
    htmlCod += '<td>' + arrWeekDays[2] + '</td>';
    htmlCod += '<td>' + arrWeekDays[3] + '</td>';
    htmlCod += '<td>' + arrWeekDays[4] + '</td>';
    htmlCod += '<td>' + arrWeekDays[5] + '</td>';
    htmlCod += '<td>' + arrWeekDays[6] + '</td>';
    htmlCod += '</tr>';
    htmlCod += '<tr align="center">';
    
    month = parseInt(month);
    year = parseInt(year);
    var i = 0;
    var days = getDaysInMonth(month + 1, year);
    var firstOfMonth = new Date (year, month, 1);
    // возвращает день недели для первого дня месяца (0-Вс, 1-Пн, ...)
    var startingPos = firstOfMonth.getDay();
    days += startingPos;
    // проставляем пустые ячейки в начале
    for (i = 0; i < startingPos; i++) {
        if (i % 7 == 0) {
            htmlCod += '</tr><tr align="center">';
        }
        htmlCod += "<td></td>";
    }
    // отрисовываем календарь
    for (i = startingPos; i < days; i++) {
        if (i % 7 == 0) {
            htmlCod += '</tr><tr align="center">';
        }
        htmlCod += '<td><a href="' + calendarUrl + calendarYear + '-';
        var linkMonth = calendarMonth + 1;
        if (linkMonth < 10) {
            linkMonth = '0' + linkMonth;
        }
        htmlCod += linkMonth + '-';
        var linkDay = i - startingPos + 1;
        if (linkDay < 10) {
            linkDay = '0' + linkDay;
        }
        htmlCod += linkDay;
        htmlCod += '">';
        htmlCod += linkDay;
        htmlCod += '</a></td>';
    }
    // проставляем пустые ячейки в конце
    for (i = days; i < 42; i++)  {
        if (i % 7 == 0) {
            htmlCod += '</tr><tr align="center">';
        }
        htmlCod += '<td></td>';
    }
    htmlCod += '</table>';
    
    document.getElementById(calendarViewId).innerHTML = htmlCod;
    
    // отрисовка страницы навигации
    var navStringCod = '<center>';
    navStringCod += '<a href="javascript:;" onclick="setPreviousMonth();"><<</a>&nbsp;';
    navStringCod += ' ' + arrMonth[calendarMonth] + '&nbsp;' + calendarYear + ' ';
    navStringCod += '&nbsp;<a href="javascript:;" onclick="setNextMonth();">>></a>';
    navStringCod += '</center>';
    
    document.getElementById(calendarNavId).innerHTML = navStringCod;
}
function getDaysInMonth(month, year)
{
    var days;
    if (month == 1 || month == 3 || month == 5 || month == 7 || month == 8 || month == 10 || month == 12) {
        days = 31;
    } else if (month == 4 || month == 6 || month == 9 || month == 11) {
        days = 30;
    } else if (month == 2) {
        if (isLeapYear(year)) {
            days = 29;
        } else {
            days = 28;
        }
    }
    return (days);
}
function isLeapYear (year)
{
    if (((year % 4) == 0) && ((year % 100) != 0) || ((year % 400) == 0)) {
        return (true);
    } else {
        return (false);
    }
}