// JavaScript Document
var TimeToFade = 1000.0;


function show(eid) {
  var element = document.getElementById(eid);
  if(element == null)
    return;

	element.style.visibility="visible";
	element.style.display="block";
}

function hide(eid) {
	  var element = document.getElementById(eid);
  if(element == null)
    return;

	element.style.visibility="hidden";
	element.style.display="none";
}


function changePicture(eid)
{
  var element = document.getElementById(eid);
  if(element == null)
    return;
	
	var src = "images/door/Youtopia-";
	var num = Math.floor(Math.random()*12)+1;
	src = src + num+".jpg";
	
	element.src = src;
	
}


function fade(eid, time)
{
	
	time=time+2000;
  var element = document.getElementById(eid);
  if(element == null)
    return;
	
  element.fadeTimer=time;
   
  if(element.FadeState == null)
  {
    if(element.style.opacity == null
        || element.style.opacity == ''
        || element.style.opacity == '1')
    {
      element.FadeState = 2;
    }
    else
    {
      element.FadeState = -2;
    }
  }
   
  if(element.FadeState == 1 || element.FadeState == -1)
  {
    element.FadeState = element.FadeState == 1 ? -1 : 1;
    element.FadeTimeLeft = time - element.FadeTimeLeft;
  }
  else
  {
    element.FadeState = element.FadeState == 2 ? -1 : 1;
    element.FadeTimeLeft = time;
    setTimeout("animateFade(" + new Date().getTime() + ",'" + eid + "')", 33);
  }  
}


function animateFade(lastTick, eid)
{  
  var curTick = new Date().getTime();
  var elapsedTicks = curTick - lastTick;
 
  var element = document.getElementById(eid);
 
  if(element.FadeTimeLeft <= elapsedTicks)
  {
    element.style.opacity = element.FadeState == 1 ? '1' : '0';
    element.style.filter = 'alpha(opacity = '
        + (element.FadeState == 1 ? '100' : '0') + ')';
    element.FadeState = element.FadeState == 1 ? 2 : -2;
	
	if(element.FadeState==-2) {
		changePicture(eid);	
		restart(eid);
		//setTimeout("restart('"+eid+"')", 3000);
	} else if (element.FadeState != -1) {
		setTimeout("restart('"+eid+"')", 5000);
	}
	
	return;
  }
 
  element.FadeTimeLeft -= elapsedTicks;
  var newOpVal = element.FadeTimeLeft/TimeToFade;
  if(element.FadeState == 1)
    newOpVal = 1 - newOpVal;

  element.style.opacity = newOpVal;
  element.style.filter = 'alpha(opacity = ' + (newOpVal*100) + ')';
 
  setTimeout("animateFade(" + curTick + ",'" + eid + "')", 33);
}

function restart(eid) 
{
  
  var element = document.getElementById(eid);
  fade(eid, Math.floor(Math.random()*5000));
}