function towerad_init(){
	if(!currentTowerAd){
		currentTowerAd = 1;
		$('towerad'+currentTowerAd).setStyle({display: 'block'});
	}

	for(i=2;i<=countTowerAd;i++){
		$('towerad'+i).setStyle({display: 'none'});
	}
	
	new PeriodicalExecuter(changeTowerAd, 7);
}

function changeTowerAd(){
		if(currentTowerAd==countTowerAd){
			nextTowerAd=1;
		}else{
			nextTowerAd = currentTowerAd+1;
		}
		

//		new Effect.Opacity($('towerad'+currentTowerAd), {duration:0.3, from:1.0, to:0.0,sync: false, afterFinish: hide,queue: {position: 'front', scope: 'towerAd'}});
		hide();
		show();
}

function hide(){
	$('towerad'+currentTowerAd).setStyle({display: 'none'});
	//new Effect.Opacity($('towerad'+nextTowerAd), {duration:0.3, from:0.0, to:1.0,sync: false, beforeUpdate: show,queue: {position: 'front', scope: 'towerAd'}});
}

function show(){
	$('towerad'+nextTowerAd).setStyle({display: 'block'});
	currentTowerAd = nextTowerAd;
}


Event.observe(window, 'load',towerad_init);