function setBackground(divName) {
	var date=new Date();
	var hour=date.getHours();
	if (hour >= 21) {
		document.getElementById(divName).style.background = "url('images/bg-stars.jpg')";
	} 
	else if (hour >= 20) {
		document.getElementById(divName).style.background = "url('images/bg-clouds_stars.jpg')";
	}
	else if (hour >= 7) {
		document.getElementById(divName).style.background = "url('images/bg-clouds.jpg')";
	} 
	else if (hour >= 6) {
		document.getElementById(divName).style.background = "url('images/bg-clouds_stars.jpg')";
	}
	else if (hour >= 0) {
		document.getElementById(divName).style.background = "url('images/bg-stars.jpg')";
	} 
	else {
		document.getElementById(divName).style.background = "url('images/bg-clouds.jpg')";
	}
}

function changeSign (signText) {
	document.getElementById('sign-text').innerHTML = signText;
}

function showOverlay(overlayBox, overlayName) {
	setTimeout('openDiv("youtube")', 300);
	keepoverlay = 0;
	fadeIn(overlayBox);
	document.getElementById(overlayBox).style.display = 'block';
	document.getElementById(overlayName).style.display = 'block';
	setTimeout('youtubePlay()', 2500);
}

function keepOverlay (value) {
	keepoverlay = value;
}

function closeOverlay() {		
	if (keepoverlay != 1) {
		youtubePause();
		closeDiv('youtube');
		fadeOut('overlay_box');
		setTimeout('doCloseOverlay()', 300);
	}
	else {
		keepoverlay = 0;
	}
}
function doCloseOverlay() {
	var overlaydivs = document.getElementsByTagName('div');
	for (var i = 0; i < overlaydivs.length; i++) {
		var overlaydiv = overlaydivs[i];
		if (overlaydiv.id.indexOf('overlay_') == 0 && overlaydiv.style) {
			overlaydiv.style.display = 'none';
		}
	}
}

function changeFotofolder(folderId)	{
	if (document.getElementById(folderId).style.display == 'block') {
		document.getElementById(folderId).style.display = 'none';
	}
	else {
		var overlaydivs = document.getElementsByTagName('div');
		for (var i = 0; i < overlaydivs.length; i++) {
			var overlaydiv = overlaydivs[i];
			if (overlaydiv.id.indexOf('folder_') == 0 && overlaydiv.style) {
				overlaydiv.style.display = 'none';
			}
		}
		document.getElementById(folderId).style.display = 'block';
	}
}

function setImage(imageID, imageName) {
	document.getElementById(imageID).src = imageName;
}
function openDiv(divName) {
	document.getElementById(divName).style.display = 'inline';
}
function closeDiv(divName) {
	document.getElementById(divName).style.display = 'none';
}

function createCache() {
	cache = Math.floor(Math.random()*999);
}

function validateGastenboek(naam, bericht) {
	if (naam != '' & bericht != '') {
		closeDiv('gastenboek-fout');
		createCache();
		DoAJAX('functions/gastenboek.php?mode=write&naam='+ naam + '&bericht=' + bericht);
		DoAJAX('functions/gastenboek.php?mode=read&from=0&cache=' + cache, 'gastenboek-lezen');
		document.gastenboek.naam.value = '';
		document.gastenboek.bericht.value = '';
		closeDiv('gastenboek-schrijven');
		openDiv('gastenboek-lezen');
	}
	else {
		openDiv('gastenboek-fout');
	}
}

function textareaCounter() {
  if ( document.gastenboek.bericht.value.length > 255 ) {
  	document.gastenboek.bericht.value = document.gastenboek.bericht.value.substring( 0, 255 );
		return false;
  }
  else {	
  	document.getElementById('gastenboek-counter').innerHTML = document.gastenboek.bericht.value.length;
  }
}

function DoAJAX(ajaxURL, divName) {
  if (window.XMLHttpRequest) {             
    AJAX=new XMLHttpRequest();             
  } else {                                 
    AJAX=new ActiveXObject("Microsoft.XMLHTTP");
  }
  if (AJAX) {
		AJAX.open("GET", ajaxURL, false);                             
		AJAX.send(null);
		if (divName != undefined ) {
			document.getElementById(divName).innerHTML = AJAX.responseText;
		}
	}
}

function youtubePlay() {
if (document.getElementById('overlay_filmpjes').style.display == 'block') {
	youtubeplayer.playVideo();
	}
}
function youtubePause() {
	if (document.getElementById('overlay_filmpjes').style.display == 'block') {
		youtubeplayer.pauseVideo();
	}
}

var fadeDuration = 150;
var fadeSteps = 15;
function fade(level) {
  document.getElementById(fadeid).style.opacity = level;
  document.getElementById(fadeid).style.MozOpacity = level;
  document.getElementById(fadeid).style.KhtmlOpacity = level;
  document.getElementById(fadeid).style.filter = "alpha(opacity=" + (level * 100) + ");";
}
function fadeIn(divid){
  fadeid = divid;
  for (i = 0; i <= 1; i += (1 / fadeSteps)) {
    setTimeout("fade(" + i + ")", i * fadeDuration);
  }
}
function fadeOut(divid) {
  fadeid = divid;
  for (i = 0; i <= 1; i += (1 / fadeSteps)) {
    setTimeout("fade(" + (1 - i) + ")", i * fadeDuration);
  }
}

function slider (id, x) {
	document.getElementById('airplane').style.left = "-750px";
	slider.obj=document.layers? document.layers[id] : document.all? document.all[id].style : document.getElementById? document.getElementById(id).style : null;
	if(slider.obj&&!slider.going) {
		slider.x=x<0? -1 : 1;
		slider.xa=x*slider.x;
		slider.going=1;
		slider.doit();
	}
}
slider.px=document.layers? '' : 'px';
slider.doit=function() {
	slider.obj.left = parseInt(slider.obj.left) + slider.x*slider.speed + slider.px;
	if(slider.xa>0) {
		slider.xa-=slider.speed;
		setTimeout("slider.doit()", slider.xa<5*slider.speed? 30 : slider.xa<10*slider.speed? 20 : 15);
	}
	else {
		slider.going=0;
		setTimeout("slider('airplane',2750)", 5000);
	}
}
slider.speed=2;

document.oncontextmenu = function() {
	return false;
}