var ptown_ad_interval = 0;
function ptown_animate_ads()
{
	if (! ptown_ad_interval) ptown_animate_ads_preload();
	else
	{
		var spot;
		var index;
		var lastIndex;
		var ad;
		var picture;
		for (var k in ptown_ads)
		{
			spot = ptown_ads[k];
			lastIndex = spot.index;
			index = lastIndex + 1;
			if (index >= spot.ads.length) index = 0;
			
			spot.index = index;
			
			if (picture = xGetElementById('ptown_ad_' + spot.id))
			{
				picture.src = spot.ads[index].image.src;
			}
			/*
			else if (picture = xGetElementById('ptown_ad_' + spot.id + '_' + spot.ads[index]))
			{
				xVisibility('ptown_ad_' + spot.id + '_' + spot.ads[lastIndex], 0);
				xVisibility('ptown_ad_' + spot.id + '_' + spot.ads[index], 1);
			}
			*/
		}
	}
}

function ptown_ad_click(id) 
{
	
	var spot = ptown_ads['db_' + id];
	if (spot) 
	{
		var ad = spot.ads[spot.index];
		if (ad && ad.url) open(ad.url);
	}
	return false;
}


function ptown_ad_over(id) 
{
	
	var spot = ptown_ads['db_' + id];
	if (spot) 
	{
		var ad = spot.ads[spot.index];
		if (ad && ad.url) window.status = 'Visit ' + ad.url;
	}
	return true;
}


function ptown_animate_ads_preload()
{
	var spot;
	var ad;
	var z;
	var foundPic = false;
	
	for (var k in ptown_ads)
	{
		spot = ptown_ads[k];
		if (spot.width)
		{
			foundPic = true;
			spot.index = 0;
			z = spot.ads.length;
			for (var i = 0; i < z; i++)
			{
				ad = spot.ads[i];
				if (i) ad.image = new Image(spot.width, spot.height);
				else 
				{
					ad.image = new Object();
					ad.image.loaded = true;
				}
				ad.image.src = ad.picture;
			}
		}
		else // it's an html ad
		{
			var index = readCookie('html' + spot.id);
			if (! index) index = 0;
			if (index >= spot.ads.length) index = 0;
			xVisibility('ptown_ad_' + spot.id + '_' + spot.ads[index], 1);
		
			index ++;
			
			createCookie('html' + spot.id, index);
		}
		
		//spot.index = spot.ads.length - 1;
	}
	if (foundPic) ptown_ad_interval = setInterval('ptown_animate_ads()', 5000);
	
	
}

// cross platform functions

function xGetElementById(e)
{
  if(typeof(e)!='string') return e;
  if(document.getElementById) e=document.getElementById(e);
  else if(document.all) e=document.all[e];
  else e=null;
  return e;
}	
function xVisibility(e, bShow)
{
  if(!(e=xGetElementById(e))) return null;
  if(e.style && xDef(e.style.visibility)) {
    if (xDef(bShow)) e.style.visibility = bShow ? 'visible' : 'hidden';
    return e.style.visibility;
  }
  return null;
}
function xDef()
{
  for(var i=0; i<arguments.length; ++i){if(typeof(arguments[i])=='undefined') return false;}
  return true;
}


// cookie handling funcitons
function createCookie(name,value,days)
{
	if (days)
	{
		var date = new Date();
		date.setTime(date.getTime()+(days*24*60*60*1000));
		var expires = "; expires="+date.toGMTString();
	}
	else var expires = "";
	document.cookie = name+"="+value+expires+"; path=/";
}

function readCookie(name)
{
	var nameEQ = name + "=";
	var ca = document.cookie.split(';');
	for(var i=0;i < ca.length;i++)
	{
		var c = ca[i];
		while (c.charAt(0)==' ') c = c.substring(1,c.length);
		if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
	}
	return null;
}

function eraseCookie(name)
{
	createCookie(name,"",-1);
}