Javascript Calendar v4

        function Calendar(inVarName, inCurrent)
        {
            var dtmToday = new Date();
            dtmToday = new Date(dtmToday.getFullYear(), dtmToday.getMonth(), dtmToday.getDate());

            var dtmCurrent = inCurrent;
            var arrMonths = new Array('Januar', 'Februar', 'Marts', 'April', 'Maj', 'Juni', 'Juli', 'August', 'September', 'Oktober', 'November', 'December');
            var arrDayNames = new Array('M', 'T', 'O', 'T', 'F', 'L', 'S');
            var strVarName = inVarName;

            var arrActiveDays = new Array();

            var objBoxCalendar = document.getElementById('BoxCalendar');
            var objWrapper = null;
            var objNaviLeft = null;
            var objCalendarYear = null;
            var objNaviRight = null;

            this.create = function ()
            {
                if (objBoxCalendar)
                {
                    CreateHeader('DayView');
                    this.viewDays(dtmCurrent);
                }
            }

            this.viewDays = function (dtmStart)
            {
                dtmStart = new Date(dtmStart);
                if (dtmStart.getDate() > 1)
                    dtmStart.setDate(1);

                for (var i = objWrapper.childNodes.length; i >= 0; i--)
                {
                    var objChild = objWrapper.childNodes[i];
                    if (objChild)
                    {
                        if (objChild.className != 'CalendarRowNavi')
                        {
                            objWrapper.removeChild(objChild);
                        }
                    }
                }

                var objCalendarRowDays = document.createElement('div');
                objCalendarRowDays.className = 'CalendarRowDays';
                objWrapper.appendChild(objCalendarRowDays);
                for (var i = 0; i < arrDayNames.length; i++)
                {
                    var objCalendarCell = document.createElement('div');
                    objCalendarCell.className = 'CalendarCell';
                    objCalendarCell.appendChild(document.createTextNode(arrDayNames[i]));
                    objCalendarRowDays.appendChild(objCalendarCell);
                    objCalendarRowDays.appendChild(document.createTextNode('\n'));
                }

                var intDaysInMonth = DaysInMonth(dtmStart.getFullYear(), dtmStart.getMonth());

                //Set the correct text and link on the top field
                while (objCalendarYear.hasChildNodes())
                {
                    objCalendarYear.removeChild(objCalendarYear.firstChild);
                }
                objCalendarYear.appendChild(document.createTextNode(arrMonths[dtmStart.getMonth()] + ' ' + dtmStart.getFullYear()));
                objCalendarYear.setAttribute('onclick', strVarName + '.viewMonths(\'' + new Date(dtmStart.getFullYear(), dtmStart.getMonth(), 1) + '\')');
                //Do the same for the navigation buttons
                objNaviLeft.setAttribute('onclick', strVarName + '.viewDays(\'' + new Date(dtmStart.getFullYear(), dtmStart.getMonth() - 1, 1) + '\')');
                objNaviRight.setAttribute('onclick', strVarName + '.viewDays(\'' + new Date(dtmStart.getFullYear(), dtmStart.getMonth() + 1, 1) + '\')');

                //Fill the first row with blank fields until we reach the starting point
                var objFirstRow = document.createElement('div');
                objFirstRow.className = 'CalendarRow';
                objWrapper.appendChild(objFirstRow);
                var intCount = 0;
                for (intCount; intCount < dtmStart.getUTCDay(); intCount++)
                {
                    var objNotThisMonth = document.createElement('div');
                    objNotThisMonth.className = 'CalendarCell NotThisMonth';
                    objFirstRow.appendChild(objNotThisMonth);
                    objFirstRow.appendChild(document.createTextNode('\n'));
                }

                //Fill the rest of the first row with days
                for (intCount; intCount < 7; intCount++)
                {
                    var objCalendarCell = document.createElement('div');
                    objCalendarCell.className = 'CalendarCell';

                    for (var j = 0; j < arrActiveDays.length; j++)
                    {
                        var dtmActiveDay = arrActiveDays[j];
                        var blnIsActiveDay = dtmActiveDay.getTime() == dtmStart.getTime();
                        var strLink = 'window.open(\'/?';
                        strLink += blnIsActiveDay ? 'ci=' : 'ci2=';   // Choose the querystring parameter
                        strLink += dtmStart.getFullYear() + '-' + eval(dtmStart.getMonth() + 1) + '-' + dtmStart.getDate() + '\', \'_self\');'
                        objCalendarCell.setAttribute('onclick', strLink);
                        if (blnIsActiveDay)
                        {
                            objCalendarCell.className += ' Active';
                            break;
                        }
                    }

                    if (dtmToday.getTime() == dtmStart.getTime())
                    {
                        if (dtmCurrent.getTime() == dtmStart.getTime())
                        {
                            objCalendarCell.className += ' Today';
                        }
                        else
                        {
                            objCalendarCell.className += ' TodayNotChosen';
                        }
                    }
                    else if (dtmCurrent.getTime() == dtmStart.getTime())
                    {
                        objCalendarCell.className += ' Chosen';
                    }

                    objCalendarCell.appendChild(document.createTextNode(dtmStart.getDate()));
                    objFirstRow.appendChild(objCalendarCell);
                    objFirstRow.appendChild(document.createTextNode('\n'));
                    dtmStart.setDate(dtmStart.getDate() + 1);
                }

                var objCalendarRow = document.createElement('div');
                objCalendarRow.className = 'CalendarRow';

                //Fill each row with days
                for (var i = dtmStart.getDate(); i <= intDaysInMonth; i++)
                {
                    if (dtmStart.getUTCDay() == 0)
                    {
                        objWrapper.appendChild(document.createTextNode('\n'));
                        objCalendarRow = document.createElement('div');
                        objCalendarRow.className = 'CalendarRow';
                        objWrapper.appendChild(objCalendarRow);
                    }

                    var objCalendarCell = document.createElement('div');
                    objCalendarCell.className = 'CalendarCell';

                    for (var j = 0; j < arrActiveDays.length; j++)
                    {
                        var dtmActiveDay = arrActiveDays[j];
                        var blnIsActiveDay = dtmActiveDay.getTime() == dtmStart.getTime();

                        var strLink = 'window.open(\'/?';
                        strLink += blnIsActiveDay ? 'ci=' : 'ci2=';   // Choose the querystring parameter
                        strLink += dtmStart.getFullYear() + '-' + eval(dtmStart.getMonth() + 1) + '-' + dtmStart.getDate() + '\', \'_self\');'
                        objCalendarCell.setAttribute('onclick', strLink);
                        if (blnIsActiveDay)
                        {
                            objCalendarCell.className += ' Active';
                            break;
                        }
                    }

                    if (dtmToday.getTime() == dtmStart.getTime())
                    {
                        if (dtmCurrent.getTime() == dtmStart.getTime())
                        {
                            objCalendarCell.className += ' Today';
                        }
                        else
                        {
                            objCalendarCell.className += ' TodayNotChosen';
                        }
                    }
                    else if (dtmCurrent.getTime() == dtmStart.getTime())
                    {
                        objCalendarCell.className += ' Chosen';
                    }

                    objCalendarCell.appendChild(document.createTextNode(dtmStart.getDate()));
                    objCalendarRow.appendChild(objCalendarCell);
                    objCalendarRow.appendChild(document.createTextNode('\n'));

                    dtmStart.setDate(dtmStart.getDate() + 1);
                }

                //Fill the rest of the last row with blank fields
                for (var i = dtmStart.getUTCDay(); i < 7; i++)
                {
                    var objNotThisMonth = document.createElement('div');
                    objNotThisMonth.className = 'CalendarCell NotThisMonth';
                    objCalendarRow.appendChild(objNotThisMonth);
                    objCalendarRow.appendChild(document.createTextNode('\n'));
                }

            }

            this.viewMonths = function (dtmStart)
            {
                dtmStart = new Date(dtmStart);
                if (dtmStart.getDate() > 1)
                    dtmStart.setDate(1);

                for (var i = objWrapper.childNodes.length; i >= 0; i--)
                {
                    var objChild = objWrapper.childNodes[i];
                    if (objChild)
                    {
                        if (objChild.className != 'CalendarRowNavi')
                        {
                            objWrapper.removeChild(objChild);
                        }
                    }
                }

                //Set the correct text and link on the top field
                while (objCalendarYear.hasChildNodes())
                {
                    objCalendarYear.removeChild(objCalendarYear.firstChild);
                }
                objCalendarYear.appendChild(document.createTextNode(dtmStart.getFullYear()));
                objCalendarYear.setAttribute('onclick', strVarName + '.viewYears(\'' + new Date(dtmStart.getFullYear(), 0, 1) + '\')');
                //Do the same for the navigation buttons
                objNaviLeft.setAttribute('onclick', strVarName + '.viewMonths(\'' + new Date(dtmStart.getFullYear() - 1, dtmStart.getMonth(), 1) + '\')');
                objNaviRight.setAttribute('onclick', strVarName + '.viewMonths(\'' + new Date(dtmStart.getFullYear() + 1, dtmStart.getMonth(), 1) + '\')');

                var objCalendarMonthRow = null;

                for (var i = 0; i < arrMonths.length; i++)
                {
                    if (i % 3 == 0)
                    {
                        objCalendarMonthRow = document.createElement('div');
                        objCalendarMonthRow.className = 'CalendarMonthRow';
                        objWrapper.appendChild(objCalendarMonthRow);
                    }

                    var objCalendarCell = document.createElement('div');
                    objCalendarCell.className = 'CalendarCell';
                    objCalendarCell.appendChild(document.createTextNode(arrMonths[i]));
                    objCalendarCell.appendChild(document.createTextNode('\n'));
                    objCalendarCell.setAttribute('onclick', strVarName + '.viewDays(\'' + new Date(dtmStart.getFullYear(), i, 1) + '\')');
                    objCalendarMonthRow.appendChild(objCalendarCell);
                    objCalendarMonthRow.appendChild(document.createTextNode('\n'));
                }
            }

            this.viewYears = function (dtmStart)
            {
                dtmStart = new Date(dtmStart);
                if (dtmStart.getDate() > 1)
                    dtmStart.setDate(1);

                for (var i = objWrapper.childNodes.length; i >= 0; i--)
                {
                    var objChild = objWrapper.childNodes[i];
                    if (objChild)
                    {
                        if (objChild.className != 'CalendarRowNavi')
                        {
                            objWrapper.removeChild(objChild);
                        }
                    }
                }

                //Set the correct text and link on the top field
                while (objCalendarYear.hasChildNodes())
                {
                    objCalendarYear.removeChild(objCalendarYear.firstChild);
                }
                objCalendarYear.appendChild(document.createTextNode(dtmStart.getFullYear() + ' - ' + eval(dtmStart.getFullYear() + 11)));
                //Do the same for the navigation buttons
                objNaviLeft.setAttribute('onclick', strVarName + '.viewYears(\'' + new Date(dtmStart.getFullYear() - 12, 0, 1) + '\')');
                objNaviRight.setAttribute('onclick', strVarName + '.viewYears(\'' + new Date(dtmStart.getFullYear() + 12, 0, 1) + '\')');

                var objCalendarYearRow = null;

                for (var i = 0; i < 12; i++)
                {
                    if (i % 3 == 0)
                    {
                        objCalendarYearRow = document.createElement('div');
                        objCalendarYearRow.className = 'CalendarYearRow';
                        objWrapper.appendChild(objCalendarYearRow);
                    }

                    var objCalendarCell = document.createElement('div');
                    objCalendarCell.className = 'CalendarCell';
                    objCalendarCell.appendChild(document.createTextNode(eval(dtmStart.getFullYear() + i)));
                    objCalendarCell.appendChild(document.createTextNode('\n'));
                    objCalendarCell.setAttribute('onclick', strVarName + '.viewMonths(\'' + new Date(eval(dtmStart.getFullYear() + i), 0, 1) + '\')');
                    objCalendarYearRow.appendChild(objCalendarCell);
                    objCalendarYearRow.appendChild(document.createTextNode('\n'));
                }
            }

            this.addActiveDay = function (inDate)
            {
                arrActiveDays[arrActiveDays.length] = inDate;
            }

            CreateHeader = function (inType)
            {
                var objHeader = document.createElement('div');
                objHeader.className = 'Header';

                var objHeaderImage = document.createElement('img');
                objHeaderImage.src = '/gfx/box/headers/calendar.png';
                objHeaderImage.width = '16';
                objHeaderImage.width = '151';
                objHeaderImage.alt = 'Maritim Kalender';
                objHeader.appendChild(objHeaderImage);

                var objContent = document.createElement('div');
                objContent.className = 'Content';

                objWrapper = document.createElement('div');
                objWrapper.className = 'CalendarWrapper';
                objContent.appendChild(objWrapper);

                var objCalendarRowNavi = document.createElement('div');
                objCalendarRowNavi.className = 'CalendarRowNavi';
                objWrapper.appendChild(objCalendarRowNavi);
                objCalendarRowNavi.appendChild(document.createTextNode('\n'));

                objNaviLeft = document.createElement('div');
                objNaviLeft.className = 'CalendarCell NaviLeft';
                objCalendarRowNavi.appendChild(objNaviLeft);
                objCalendarRowNavi.appendChild(document.createTextNode('\n'));

                objCalendarYear = document.createElement('div');
                objCalendarYear.className = 'CalendarCell CalendarYear';
                objCalendarRowNavi.appendChild(objCalendarYear);
                objCalendarRowNavi.appendChild(document.createTextNode('\n'));

                objNaviRight = document.createElement('div');
                objNaviRight.className = 'CalendarCell NaviRight';
                objCalendarRowNavi.appendChild(objNaviRight);

                while (objBoxCalendar.hasChildNodes())
                {
                    objBoxCalendar.removeChild(objBoxCalendar.firstChild);
                }
                objBoxCalendar.appendChild(objHeader);
                objBoxCalendar.appendChild(objContent);
            }

            DaysInMonth = function (year, month)
            {
                return 32 - new Date(year, month, 32).getDate();
            }
        }