function popUp(URL, w, h) {
	day = new Date();
	id = day.getTime();
	eval("page" + id + " = window.open(URL, '" + id + "', 'toolbar=0,scrollbars=0,location=0,statusbar=0,menubar=0,resizable=0,width="+w+",height="+h+",left = 0,top = 0');");
}

function popupSmallWin() {
	smallWin = window.open("","smallWin", 'toolbar=0,scrollbars=0,location=0,statusbar=0,menubar=0,resizable=0,width=200,height=200');
	document.searchavail.submit();
}




/*

	Calendar.js
	Copyright 2003, Qualion.nl
	
	Maakt de functie MakeCalendar beschikbaar,
	die een kalender voor een opgegeven maand/jaar maakt,
	in de gewenste taal, met closed days.
	
	Parameters:
	month:	De maand
	year:	Het jaar
	lang:		Taal
	closed:	de closed days, als kommagescheiden *string*.
	
*/

function MakeCalendar (month,year,lang,closed) {
	if (lang == 'nl') {
		var day_of_week = new Array('z','m','d','w','d','v','z');
		var month_of_year = new Array('Januari','Februari','Maart','April','Mei','Juni','Juli','Augustus','September','Oktober','November','December');
		var availstring = 'Beschikbaarheid';		
	} else {
    if (lang == 'de'){
		  var day_of_week = new Array('s','m','d','m','d','f','s');
		  var month_of_year = new Array('Januar','Februar','März','April','Mai','Juni','Juli','August','September','Oktober','November','Dezember');
		  var availstring = 'Verfügbarkeit';		
	  } else {
        var day_of_week = new Array('s','m','t','w','t','f','s');
	  	   var month_of_year = new Array('January','February','March','April','May','June','July','August','September','October','November','December');
		    var availstring = 'Availability';
    }
  }
	
	// De maand 1 verlagen
	month--;
	
	// Closed days in een array zetten
	closed = closed.split(',');
	
	// Kalender aanmaken, paar variabelen instellen
	var Calendar = new Date(year,month,1);
	var cal;
	var tr_start = '<tr class="CalendarRow">';
	var tr_end = '</tr>';
	var td_closed = '<td class="CalendarClosed">';
	var td_empty = '<td class="CalendarEmpty">&nbsp;</td>';
	var td_start = '<td class="CalendarCell">';
	var td_end = '</td>';
	
	// Beginnen met de kalender
	cal = '<table class="Calendar" cellspacing="1" cellpadding="1" width="100%">' + tr_start;
	cal += '<th colspan="7" class="CalendarHeader">';
	cal += month_of_year[month]  + '   ' + year; // Het kopje
	cal += '<br />' + availstring;
	cal += '</th>' + tr_end + tr_start;
		
	// Dagkopjes
	for (index=0; index < 7; index++) {
		cal += td_start + day_of_week[index] + td_end;
	}
	
	// ...volgende regel...
	cal += td_end + tr_end;
	cal += tr_start;
	
	// Lege vakjes tot de 1e van de maand
	for (index=0; index < Calendar.getDay(); index++) {
		cal += td_empty;
	}
	
	// Dagen aflopen
	for (index=0; index < 31; index++) {
		if( Calendar.getDate() > index ) {
			// What day do you want to handle today? (tm)
			week_day =Calendar.getDay();
			
			// Voor de eerste dag van de week een nieuwe regel
			if(week_day == 0) {
				cal += tr_start;
			}
			
			if(week_day != 7) {
				// Weekdag is ook daadwerkelijk een weekdag
				var day  = Calendar.getDate();
			
				// Closed date?
				if( closed[0] == Calendar.getDate() ) {
					// Yup, X
					cal += td_closed + day + td_end;
					closed.shift();
				} else {
					// Nope, dag
					cal += td_start + day + td_end;
				}
			}
			
			// Einde regel
			if(week_day == 7)
			cal += tr_end;
		}
		
		// Volgende...
		Calendar.setDate(Calendar.getDate()+1);
		
	}// einde 31 dagen
	
	// Laatste stukje ook opvullen
	while (week_day < 6) {
		cal += td_empty;
		week_day++;
	}
	
	// Einde tabel
	cal += '</td></tr></table>';
	
	//  Spuug...
	document.write(cal);
}




<!-- DateDiff Script: Berekent aantal dagen tussen twee data -->
function isValidDate(dateStr) 
{
	// Checks for the following valid date formats:
	// MM/DD/YY   MM/DD/YYYY   MM-DD-YY   MM-DD-YYYY

	var datePat = /^(\d{1,2})(\/|-)(\d{1,2})\2(\d{4})$/; // requires 4 digit year

	var matchArray = dateStr.match(datePat); // is the format ok?
	if (matchArray == null) 
	{
		alert(dateStr + " Date is not in a valid format.")
		return false;
	}
	
	month = matchArray[1]; // parse date into variables
	day = matchArray[3];
	year = matchArray[4];
	if (month < 1 || month > 12) 
	{ // check month range
		alert("Month must be between 1 and 12.");
		return false;
	}

	if (day < 1 || day > 31) 
	{
		alert("Day must be between 1 and 31.");
		return false;
	}
	
	if ((month==4 || month==6 || month==9 || month==11) && day==31) 
	{
		alert("Month "+month+" doesn't have 31 days!")
		return false;
	}
	if (month == 2) 
	{ // check for february 29th
		var isleap = (year % 4 == 0 && (year % 100 != 0 || year % 400 == 0));
		if (day>29 || (day==29 && !isleap)) 
		{
			alert("February " + year + " doesn't have " + day + " days!");
			return false;
	  	}
	}
	
	return true;
}




<!-- Stuurt de data-option veldjes aan en slaat waarden op -->
var _now = new Date();
var _availDate = new Date(_now.getTime());
var _departDate = new Date(_now.getTime() + 1*24*60*60*1000);
var arrmonth = _availDate.getMonth()+1; 
var depmonth = _departDate.getMonth()+1;
var arrday = _availDate.getDate();	
var depday = _departDate.getDate();	


function Init ()
{
	_availDate = new Date(_now.getTime());
	_departDate = new Date(_now.getTime() + 1*24*60*60*1000);
}
	
function isBrowserSupp() 
{
	    // Get the version of the browser
	    version =  parseFloat( navigator.appVersion );
	
	    if ( ( version >= 2.0 ) && ( version < 2.1 ) && ( navigator.appName.indexOf( "Netscape" ) != -1 ) ) 
	    {
	        return false;
	    }
	    else 
	    {
	    	return true;
	    }
	
	return true;
}

function isLeapYear(yrStr)
{
	var leapYear=false;
	var year = parseInt(yrStr, 10);
	// every fourth year is a leap year
	if (year%4 == 0)
	{
	    leapYear=true;
	    // unless it's a multiple of 100
	    if (year%100 == 0)
	    {
	        leapYear=false;
	        // unless it's a multiple of 400
	        if (year%400 == 0)
	        {
	            leapYear=true;
	        }
	    }
	}
	return leapYear;
}


function getDaysInMonth(mthIdx, YrStr)
{
	// all the rest have 31
	var maxDays=31
	// expect Feb. (of course)
	if (mthIdx==1)
	{
	    if (isLeapYear(YrStr))
	    {
	        maxDays=29;
	    }
	    else
	    {
	        maxDays=28;
	    }
	}
	// thirty days hath...
	if (mthIdx==3 || mthIdx==5 || mthIdx==8 || mthIdx==10)
	{
	    maxDays=30;
	}
	return maxDays;
}


//the function which does some magic to the date fields
// return non-zero if it is the last day of the month
function adjustDate(mthIdx, Dt)
{
	var value=0;

	var today = new Date()
	var theYear = parseInt(today.getYear(),10)

	if (mthIdx < today.getMonth()) 
	{
    		theYear = (parseInt(today.getYear(), 10) + 1)
	}
	if(theYear<100)
	{
    		theYear = "19" + theYear
	}
	else
	{
    		if((theYear-100) < 10)
    		{
        		theYear = "0" + (theYear-100)
    		}
    		else
    		{
        		theYear = (theYear-100)+""
         	}
    		theYear = "20" + theYear
	}


	var numDays=getDaysInMonth(mthIdx, theYear);

	if (mthIdx==1)
	{
	    if (Dt.options.selectedIndex + 1 < numDays)
	    {
	        return 0;
	    }
	    else
	    {
	        Dt.options.selectedIndex=numDays - 1;
	        //check for leap year
	        if (numDays==29)
	        {
	            return 99;
	        }
	        else
	        {
	            return 1;
	        }
	     }
	}
	if (Dt.options.selectedIndex + 1 < numDays)
	{
	    value=0;
	}
	else
	{
	    if (Dt.options.selectedIndex + 1 > numDays)
	    {
	        Dt.options.selectedIndex--;
	        value=3;
	    }
	    else
	    {
	        //index is 31 or 30
	        value=2;
	    }
	}
	return value;
}

//changes departure month when arrival month is changed
function amadChange(inM,inD,outM,outD)
{
	if (!isBrowserSupp())
	{
	    return;
	}
	
	var res = adjustDate(inM.options.selectedIndex, inD);
	if (res != 0)
	{
	           outD.options.selectedIndex=0;
	           if (outM.options.selectedIndex==11)
	           {
	            outM.options.selectedIndex=0
	           }
	           else
	           {
	            outM.options.selectedIndex=inM.options.selectedIndex + 1;
	           }
	}
	else
	{
	    outM.options.selectedIndex = inM.options.selectedIndex;
	    outD.options.selectedIndex = inD.options.selectedIndex+1;
	}

}

function dmddChange(outM,outD)
{
	if (!isBrowserSupp())
	{
	    return;
	}
	
	adjustDate(outM.options.selectedIndex,outD);

	return;
}





/* --- Functions for handling mouse scrolling --- */
function handle(delta) {
	if (delta < 0) {
		map.zoomOut();
	} else {
		map.zoomIn();
	}
}
function wheel(event){
	var delta = 0;
	if (!event) event = window.event;
	if (event.wheelDelta) {
		delta = event.wheelDelta/120; 
		if (window.opera) delta = -delta;
	} else if (event.detail) {
		delta = -event.detail/3;
	}
	if (delta) {
		handle(delta);
		if (event.preventDefault) event.preventDefault();
		event.returnValue = false;
	}
}

/* --- Function to put the hotels on the map --- */
function HotelsnlCreateMap(map,hotelinfo, lang){
	var arrlength = hotelinfo.length;
	var bounds = map.getBounds();
 	var sw = bounds.getSouthWest();
 	var ne = bounds.getNorthEast();
 	var left = sw.lng();
 	var right = ne.lng();
 	var up = ne.lat();
	var down = sw.lat();
  	
	function createMarker(point, label, link) {
		var marker = new GMarker(point, icon);
		map.addOverlay(marker);
		GEvent.addListener(marker, "mouseover", function() {  marker.openInfoWindowHtml(label); });
		GEvent.addListener(marker, "click", function() { window.location=link; });
		return marker;
	}
  
	for(var i = 0; i <= arrlength-1; i++){
  		var icon = new GIcon();
  		icon.image = "http://www.hotels.nl/img/avmap/star"+hotelinfo[i][4]+".png";
  		icon.shadow = "http://www.hotels.nl/img/avmap/schaduw.png";
  		icon.iconSize = new GSize(22, 21);
  		icon.iconAnchor = new GPoint(6, 20);
  		icon.infoWindowAnchor = new GPoint(5, 1);
  		var point = new GLatLng(hotelinfo[i][2],hotelinfo[i][3]);
  		createMarker(point, ''+hotelinfo[i][0]+'<br />'+hotelinfo[i][1]+'', 'hotel.php?hotelid='+hotelinfo[i][5]+'&lang='+lang);
	}
	return(map);
}

/* --- This function calculates the average lon or lat to determine the center --- */
function average() {
	var items = average.arguments.length;
	var sum = 0;
	for (i = 0; i < items;i++) {
		sum += parseFloat(average.arguments[i]);
	}
	return (sum/items);
}

/* --- This function puts the map on the div with id="map" --- */
function load() {
	if (GBrowserIsCompatible()) {
		// Determine the center of the map
		var arrlength = hoteldata.length;
		var hoteldatalats = '';
		var hoteldatalons = '';
		for(var i = 0;i < arrlength;i++){
			hoteldatalats += hoteldata[i][2]+',';
			hoteldatalons += hoteldata[i][3]+',';
		}
		var hotellat2 = average(hoteldatalats);
		var hotellon2 = average(hoteldatalons);

		// Default zoom level
		var zoom = 13;

		// Create the map
		map = new GMap2(document.getElementById("map"));

		/* Put the zoom controls on the map.
		   GSmallMapControl is the small version. You can unescape it to use
		   it. You`ll have to escape the GLargeMapControl
		*/
		//map.addControl(new GSmallMapControl());
		map.addControl(new GLargeMapControl());

		map.addControl(new GMapTypeControl());		// The map types (map, satellite OR hybrid)(upper right corner)
		map.addControl(new GScaleControl());		// Displays the scale (lowerleft corner)
		map.addControl(new GOverviewMapControl());	// Display a small map in the lower right corner
		map.enableScrollWheelZoom();			// Zoom in and out with your mousewheel

		map.setCenter(new GLatLng(hotellat2, hotellon2), zoom);	// Sets the center of the map
		map = HotelsnlCreateMap(map, hoteldata, lang);		// Puts the hotels on the map
		 
		// This block is used for zooming in and out with the mousewheel.
	/*	if (window.addEventListener) {
			window.addEventListener('DOMMouseScroll', wheel, false);
		} else {
			window.onmousewheel = document.onmousewheel = wheel;
		}*/
	}
}