//============================
// Calendar Object Constructor
//============================
function calendarObj () {
	this.isIE = (document.all ? true : false);
	this.isDOM = (document.getElementById ? true : false);

	this.months = new Array("Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul",
							"Aug", "Sep", "Oct", "Nov", "Dec");
    this.daysInMonth = new Array(31, 28, 31, 30, 31, 30, 31, 31,
								 30, 31, 30, 31);
	this.displayMonth = new Date().getMonth();
	this.displayYear = new Date().getFullYear();
	this.displayDivName = null;
	this.displayElement = null;
}

//=================================
// Calendar Object getDays function
//=================================
function calendarObj_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 this.daysInMonth[month];
}

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

////////////////////////////////////////////////////////////////////////////

// overly simplistic test for IE
isIE = (document.all ? true : false);

// both IE5 and NS6 are DOM-compliant
isDOM = (document.getElementById ? true : false);

// get the true offset of anything on NS4, IE4/5 & NS6, even if it's in a table!
function getAbsX(elt) {
	return (elt.x) ? elt.x : getAbsPos(elt,"Left") + elt.width; 
}

function getAbsY(elt) { 
	return (elt.y) ? elt.y : getAbsPos(elt,"Top"); 
}

function getAbsPos(elt,which) {
	iPos = 0;
	while (elt != null) {
		iPos += elt["offset" + which];
		elt = elt.offsetParent;
	}
	return iPos;
}

function getDivStyle(divname) {
	var style;
	if (isDOM) { 
		style = document.getElementById(divname).style; 
	} else { 
		style = isIE ? document.all[divname].style : document.layers[divname]; 
	} // NS4
	return style;
}

function hideElement(divname) {
	getDivStyle(divname).visibility = 'hidden';
}

// annoying detail: IE and NS6 store elt.top and elt.left as strings.
function moveBy(elt,deltaX,deltaY) {
	elt.left = parseInt(elt.left) + deltaX;
	elt.top = parseInt(elt.top) + deltaY;
}

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 toggleVisible(divname) {
	divstyle = getDivStyle(divname);
	if (divstyle.visibility == 'visible' || divstyle.visibility == 'show') {
		divstyle.visibility = 'hidden';
	} else {
		fixPosition(divname);
		divstyle.visibility = 'visible';
	}
}

function fixPosition(divname) {
	divstyle = getDivStyle(divname);
	positionerImgName = divname + 'Pos';
	// hint: try setting isPlacedUnder to false
	isPlacedUnder = false;
	if (isPlacedUnder) {
		setPosition(divstyle,positionerImgName,true);
	} else {
		setPosition(divstyle,positionerImgName)
	}
}

function setPosition(elt,positionername,isPlacedUnder) {
	var positioner;
	if (isIE) {
		positioner = document.all[positionername];		
	} else {
		if (isDOM) {
			positioner = document.getElementById(positionername);
		} else {
			// not IE, not DOM (probably NS4)
			// if the positioner is inside a netscape4 layer this will *not* find it.
			// I should write a finder function which will recurse through all layers
			// until it finds the named image...
			positioner = document.images[positionername];
		}
	}
	elt.left = getAbsX(positioner);
	elt.top = getAbsY(positioner) + (isPlacedUnder ? positioner.height : 0);
}


// Initialize arrays.
var months = new Array("Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul",
					   "Aug", "Sep", "Oct", "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 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 border=1 cellspacing=0 cellpadding=2><tr><td bgcolor=#ffffff nowrap>';
	daysGrid += '<font face="courier new, courier" size=2>';
	daysGrid += '<a href="javascript:hideElement(\'' + eltName + '\')">x</a>';
	daysGrid += '&nbsp;&nbsp;';
	daysGrid += '<a href="javascript:incMonth(-1,\'' + eltName + '\')">&laquo; </a>';

	daysGrid += '<b>';
	if (isThisMonth) { 
		daysGrid += '<font color=red>' + months[month] + '</font>'; 
	} 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) {
	displayElement.value = (displayMonth + 1) + "/" + day + "/" + displayYear;
	hideElement(eltName);
}