function opacity(id, opacStart, opacEnd, millisec) {
	//speed for each frame
	var speed = Math.round(millisec / 100);
	var timer = 0;

	//determine the direction for the blending, if start and end are the same nothing happens
	if(opacStart > opacEnd) {
		for(i = opacStart; i >= opacEnd; i--) {
			setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed));
			timer++;
		}
	} else if(opacStart < opacEnd) {
		for(i = opacStart; i <= opacEnd; i++)
			{
			setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed));
			timer++;
		}
	}
}

//change the opacity for different browsers
function changeOpac(opacity, id) {
	var object = document.getElementById(id).style; 
	object.opacity = (opacity / 100);
	object.MozOpacity = (opacity / 100);
	object.KhtmlOpacity = (opacity / 100);
	object.filter = "alpha(opacity=" + opacity + ")";
}

function shiftOpacity(id, millisec) {
	//if an element is invisible, make it visible, else make it ivisible
	if(document.getElementById(id).style.opacity == 0) {
		opacity(id, 0, 100, millisec);
	} else {
		opacity(id, 100, 0, millisec);
	}
}

function blendimage(divid, imageid, imagefile, millisec) {
	var speed = Math.round(millisec / 100);
	var timer = 0;
	
	//set the current image as background
	document.getElementById(divid).style.backgroundImage = "url(" + document.getElementById(imageid).src + ")";
	
	//make image transparent
	changeOpac(0, imageid);
	
	//make new image
	document.getElementById(imageid).src = imagefile;

	//fade in image
	for(i = 0; i <= 100; i++) {
		setTimeout("changeOpac(" + i + ",'" + imageid + "')",(timer * speed));
		timer++;
	}
}

function currentOpac(id, opacEnd, millisec) {
	//standard opacity is 100
	var currentOpac = 100;
	
	//if the element has an opacity set, get it
	if(document.getElementById(id).style.opacity < 100) {
		currentOpac = document.getElementById(id).style.opacity * 100;
	}

	//call for the function that changes the opacity
	opacity(id, currentOpac, opacEnd, millisec)
}

function fadeout() {
  changeOpac(50, 'gutovka');
  changeOpac(50, 'bohdalec');
  changeOpac(50, 'showroom');
  
  //LETAK RIJEN - ABITARE
  //window.open('./shop/letak.html','Akce','width=570,height=600,toolbar=yes,location=yes,directories=yes,status=yes,menubar=yes,scrollbars=yes,copyhistory=yes,resizable=yes');
  //open_adv();
  setTimeout("close_adv()",5000);
}

function open_adv(){
  opacity('reklama', 0, 80, 1500);
}

function close_adv(){
  var object = document.getElementById("reklama").style;
  if (object.opacity != 0) {
    opacity('reklama', 80, 0, 500);
  }
  object.visibility = 'hidden';
}

function select(id) {
  var el = document.getElementById(id);
  el.style.cursor='hand';
  if (document.implementation && document.implementation.createDocument) {
    el.style.backgroundImage='url(./images/home/menu_background.png)';
  }
  else if (window.ActiveXObject) {
    el.style.filter="progid:DXImageTransform.Microsoft.AlphaImageLoader(src='./images/home/menu_background.png',sizingMethod='scale')";
  }
}

function unselect(id) {
  var el = document.getElementById(id);
  if (document.implementation && document.implementation.createDocument) {
    el.style.backgroundImage='none';
  }
  else if (window.ActiveXObject) {
    el.style.filter="";
  }
}