// how reliable is this test?
isIE = (document.all ? true : false);
isDOM = (document.getElementById ? true : false);

    // Initialize arrays.
    var months = new Array("Jan", "Feb", "Mar", "Apr", "Maj", "Jun", "Jul", "Aug", "Sep", "Okt", "Nov", "Dec");
	var daysInMonth = new Array(31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31);
	var displayMonth = new Date().getMonth();
	var displayYear = new Date().getFullYear();
	var displayDivName;
	var displayElement;


    function getDays(month, year) {
        // Test for leap year when February is selected.
        if (1 == month)
           return ((0 == year % 4) && (0 != (year % 100))) ||
              (0 == year % 400) ? 29 : 28;
        else
           return daysInMonth[month];
     }

     function getToday() {
        // Generate today's date.
        this.now = new Date();
        this.year = this.now.getFullYear();
        this.month = this.now.getMonth();
        this.day = this.now.getDate();
     }

     // Start with a calendar for today.
     today = new getToday();

     function newCalendar(eltName,attachedElement) {
    if (attachedElement) {
       if (displayDivName && displayDivName != eltName) hideElement(displayDivName);
       displayElement = attachedElement;
    }
    displayDivName = eltName;
        today = new getToday();
        var parseYear = parseInt(displayYear + '');
        var newCal = new Date(parseYear,displayMonth,1);
        var day = -1;
        var startDayOfWeek = newCal.getDay();
        if ((today.year == newCal.getFullYear()) &&
              (today.month == newCal.getMonth()))
    {
           day = today.day;
        }
        var intDaysInMonth =
           getDays(newCal.getMonth(), newCal.getFullYear());
        var daysGrid = makeDaysGrid(startDayOfWeek,day,intDaysInMonth,newCal,eltName)
    if (isIE) {
       var elt = document.all[eltName];
       elt.innerHTML = daysGrid;
        } else if (isDOM) {
       var elt = document.getElementById(eltName);
       elt.innerHTML = daysGrid;
    } else {
       var elt = document.layers[eltName].document;
       elt.open();
       elt.write(daysGrid);
       elt.close();
    }
 }

 function incMonth(delta,eltName) {
   displayMonth += delta;
   if (displayMonth >= 12) {
     displayMonth = 0;
     incYear(1,eltName);
   } else if (displayMonth <= -1) {
     displayMonth = 11;
     incYear(-1,eltName);
   } else {
     newCalendar(eltName);
   }
 }
function toggleDatePicker(eltName,formElt) {
  var x = formElt.indexOf('.');
  var formName = formElt.substring(0,x);
  var formEltName = formElt.substring(x+1);
  newCalendar(eltName,document.forms[formName].elements[formEltName]);
  toggleVisible(eltName);
}
 function incYear(delta,eltName) {
   displayYear = parseInt(displayYear + '') + delta;
   newCalendar(eltName);
 }

 function makeDaysGrid(startDay,day,intDaysInMonth,newCal,eltName) {
    var daysGrid;
    var month = newCal.getMonth();
    var year = newCal.getFullYear();
    var isThisYear = (year == new Date().getFullYear());
    var isThisMonth = (day > -1)
	    daysGrid = '<table class="datePicker"><tr><td>';
	    daysGrid += '<a href="javascript:hideElement(\'' + eltName + '\')">&nbsp; </a>';
	    daysGrid += '&nbsp;&nbsp;';
	    daysGrid += '<a href="javascript:incMonth(-1,\'' + eltName + '\')">&laquo; </a>';

	    daysGrid += '<b>';
	    if (isThisMonth) { daysGrid += '<font color=red>' + months[month]; }
	    else { daysGrid += months[month]; }
	    daysGrid += '</b>';

	    daysGrid += '<a href="javascript:incMonth(1,\'' + eltName + '\')"> &raquo;</a>';
	    daysGrid += '&nbsp;&nbsp;&nbsp;';
	    daysGrid += '<a href="javascript:incYear(-1,\'' + eltName + '\')">&laquo; </a>';

	    daysGrid += '<b>';
	    if (isThisYear) { daysGrid += '<font color=red>' + year + '</font>'; }
	    else { daysGrid += ''+year; }
	    daysGrid += '</b>';

	    daysGrid += '<a href="javascript:incYear(1,\'' + eltName + '\')"> &raquo;</a><br>';
	    daysGrid += '&nbsp;Su Mo Tu We Th Fr Sa&nbsp;<br>&nbsp;';
	    var dayOfMonthOfFirstSunday = (7 - startDay + 1);
	    for (var intWeek = 0; intWeek < 6; intWeek++) {
   var dayOfMonth;
   for (var intDay = 0; intDay < 7; intDay++) {
     dayOfMonth = (intWeek * 7) + intDay + dayOfMonthOfFirstSunday - 7;
 if (dayOfMonth <= 0) {
       daysGrid += "&nbsp;&nbsp; ";
 } else if (dayOfMonth <= intDaysInMonth) {
   var color = "blue";
   if(day > 0 && day == dayOfMonth) color="red";
		   daysGrid += '<a href="javascript:setDay(';
   daysGrid += dayOfMonth + ',\'' + eltName + '\')" '
   daysGrid += 'style="color:' + color + '">';
		   var dayString = dayOfMonth + "</a> ";
		   if (dayString.length == 6) dayString = '0' + dayString;
		   daysGrid += dayString;
		 }
	       }
	       if (dayOfMonth < intDaysInMonth) daysGrid += "<br>&nbsp;";
	    }
	    return daysGrid + "</td></tr></table>";
	 }

	function setDay(day,eltName) {
		if( day < 10 && (displayMonth + 1) < 10 ){
			displayElement.value =  "0" + day + ".0" + (displayMonth + 1) + "." + displayYear;
		}
		else if( (displayMonth + 1) < 10 ){
			displayElement.value =  day + ".0" + (displayMonth + 1) + "." + displayYear;
		}
		else if( day < 10 ){
			displayElement.value =  "0" + day + "." + (displayMonth + 1) + "." + displayYear;
		}
		else{
			displayElement.value =  day + "." + (displayMonth + 1) + "." + displayYear;
		}
		
	   	hideElement(eltName);
	}