function CalendarControlNav() {

  var calendarId = 'CalendarControlNav';
  var currentYear = 0;
  var currentMonth = 0;
  var currentDay = 0;

  var selectedYear = 0;
  var selectedMonth = 0;
  var selectedDay = 0;

  var months = ['January','February','March','April','May','June','July','August','September','October','November','December'];
  var dateField = null;

  function getProperty(p_property){
    var p_elm = calendarId;
    var elm = null;

    if(typeof(p_elm) == "object"){
      elm = p_elm;
    } else {
      elm = document.getElementById(p_elm);
    }
    if (elm != null){
      if(elm.style){
        elm = elm.style;
        if(elm[p_property]){
          return elm[p_property];
        } else {
          return null;
        }
      } else {
        return null;
      }
    }
  }

  function setElementProperty(p_property, p_value, p_elmId){
    var p_elm = p_elmId;
    var elm = null;

    if(typeof(p_elm) == "object"){
      elm = p_elm;
    } else {
      elm = document.getElementById(p_elm);
    }
    if((elm != null) && (elm.style != null)){
      elm = elm.style;
      elm[ p_property ] = p_value;
    }
  }

  function setProperty(p_property, p_value) {
    setElementProperty(p_property, p_value, calendarId);
  }

  function getDaysInMonth(year, month) {
    return [31,((!(year % 4 ) && ( (year % 100 ) || !( year % 400 ) ))?29:28),31,30,31,30,31,31,30,31,30,31][month-1];
  }

  function getDayOfWeek(year, month, day) {
    var date = new Date(year,month-1,day)
    return date.getDay();
  }

  this.changeMonth = changeMonth;
  function changeMonth(change) {
    currentMonth += change;
    currentDay = 0;
    if(currentMonth > 12) {
      currentMonth = 1;
      currentYear++;
    } else if(currentMonth < 1) {
      currentMonth = 12;
      currentYear--;
    }

    calendar = document.getElementById(calendarId);
    calendar.innerHTML = calendarDrawTable();
  }

  this.changeYear = changeYear;
  function changeYear(change) {
    currentYear += change;
    currentDay = 0;
    calendar = document.getElementById(calendarId);
    calendar.innerHTML = calendarDrawTable();
  }

  function getCurrentYear() {
    var year = new Date().getYear();
    if(year < 1900) year += 1900;
    return year;
  }

  function getCurrentMonth() {
    return new Date().getMonth() + 1;
  } 

  function getCurrentDay() {
    return new Date().getDate();
  }

  function calendarDrawTable() {

    var dayOfMonth = 1;
    var validDay = 0;
    var startDayOfWeek = getDayOfWeek(currentYear, currentMonth, dayOfMonth);
    var daysInMonth = getDaysInMonth(currentYear, currentMonth);
    var css_class = null; //CSS class for each day

		var linkDay ="01";
		var linkMonth=currentMonth+'';
		if (linkMonth.length==1){
  		linkMonth='0'+linkMonth;
		}

    var table = "<table style='border:1px solid gray; border-spacing:0px; background-color:#fff; padding:0px; width:141px;' cellspacing='0'>";
    table = table + "<tr class='header' style='text-align:center; text-decoration:none'> ";
    table = table + "  <td colspan='2' class='previous' style='text-align:left;'><a href='javascript:changeCalendarControlNavMonth(-1);'><img src='images/littlearrowleft.gif' width='15' height='13' border='0' align='middle' alt='Previous Month'></a> <a href='javascript:changeCalendarControlNavYear(-1);' style='text-decoration:none; vertical-align:text-middle; color:#000000; font-size:20px;'>&laquo;</a></td>";
    table = table + "  <td colspan='4' class='title'><a href='main.php?view=month&amp;timebegin="+currentYear+"-"+linkMonth+"-01' style='color:#000090; font-weight:bold; text-decoration:none'>" + months[currentMonth-1] + "</a><br>" + currentYear + "</td>";
    table = table + "  <td colspan='2' class='next' style='text-align:right;' ><a href='javascript:changeCalendarControlNavYear(1);' style='text-decoration:none; color:#000000; font-size:20px;' alt='Next Year'>&raquo;</a> <a href='javascript:changeCalendarControlNavMonth(1);'><img src='images/littlearrowright.gif' width='15' height='13' border='0' align='middle' alt='Next Month'></a></a></td>";
    table = table + "</tr>";
    table = table + "<tr><th class='littlecalendarheader' width='16%'>&nbsp;</th><th class='littlecalendarheader' width='12%'>S</th><th class='littlecalendarheader' width='12%'>M</th><th class='littlecalendarheader' width='12%'>T</th><th class='littlecalendarheader' width='12%'>W</th><th class='littlecalendarheader' width='12%'>T</th><th class='littlecalendarheader' width='12%'>F</th><th class='littlecalendarheader' width='12%'>S</th></tr>";

		table = table + "<tr align='center'><td colspan='8' bgcolor='#ffffff'>";
		table = table + "<table width='100%' border='0' cellspacing='0' cellpadding='0'><tr><td bgcolor='#999999'><img src='images/spacer.gif' width='1' height='1'></td></tr></table>";
		table = table + "</td> </tr>";

		
    for(var week=0; week < 6; week++) {
			if ( dayOfMonth < daysInMonth+1 ){
				var firstDayofWeek = new Date(currentYear,linkMonth-1,linkDay);
        if(week == 0 && firstDayofWeek.getDay()!=0) {
					 firstDayofWeek.setDate(firstDayofWeek.getDate()-7); 
				}
				var weekno = firstDayofWeek.getWeek();
  			table = table +"<tr><td class='littlecalendarday'><a href='main.php?view=week&amp;timebegin="+currentYear+"-"+linkMonth+"-"+linkDay+"' style='text-decoration:none'>w"+weekno+"</a></td>";
			}
      for(var dayOfWeek=0; dayOfWeek < 7; dayOfWeek++) {
        if(week == 0 && startDayOfWeek == dayOfWeek) {
          validDay = 1;
        } else if (validDay == 1 && dayOfMonth > daysInMonth) {
          validDay = 0;
        }

        if(validDay) {
          if (dayOfMonth == selectedDay && currentYear == selectedYear && currentMonth == selectedMonth) {
            css_class = 'current';
          } else if (dayOfWeek == 0 || dayOfWeek == 6) {
            css_class = 'weekend';
          } else {
            css_class = 'weekday';
          }

          table = table + "<td class='littlecalendarday'><a href='main.php?view=day&amp;timebegin="+currentYear+"-"+linkMonth+"-"+linkDay+"' style='text-decoration:none'>"+dayOfMonth+"</a></td>";
          dayOfMonth++;
					linkDay = dayOfMonth+'';
					if (linkDay.length==1) {
  					linkDay = "0"+linkDay;
					}
        } else {
          table = table + "<td class='empty'>&nbsp;</td>";
        }
      }
      table = table + "</tr>";
    }

    table = table + "</table>";

    return table;
  }

  this.show = show;
  function show(dateField) {
  
    // If the calendar is visible and associated with
    // this field do not do anything.

    if(dateField) {
      try {
        var dateString = dateField
        var dateParts = dateString.split("-");
        
        selectedMonth = parseInt(dateParts[0],10);
        selectedDay = parseInt(dateParts[1],10);
        selectedYear = parseInt(dateParts[2],10);
      } catch(e) {}
    }

    if (!(selectedYear && selectedMonth && selectedDay)) {
      selectedMonth = getCurrentMonth();
      selectedDay = getCurrentDay();
      selectedYear = getCurrentYear();
    }

    currentMonth = selectedMonth;
    currentDay = selectedDay;
    currentYear = selectedYear;

    if(document.getElementById){

      calendar = document.getElementById(calendarId);
      calendar.innerHTML = calendarDrawTable(currentYear, currentMonth);
    }
  }
}

var CalendarControlNav = new CalendarControlNav();

function showCalendarControlNav(textField) {
  CalendarControlNav.show(textField);
}

function changeCalendarControlNavYear(change) {
  CalendarControlNav.changeYear(change);
}

function changeCalendarControlNavMonth(change) {
  CalendarControlNav.changeMonth(change);
}

Date.prototype.getWeek = function() {
var onejan = new Date(this.getFullYear(),0,1);
return Math.ceil((((this - onejan) / 86400000) + onejan.getDay())/7);
}