window.onload?=?function(){
	var?container?=?document.getElementById('container');
	var?photos?=?document.getElementById('photos');
	var?buttons?=?document.getElementById('buttons');
	var?prev?=?document.getElementById('prev');
	var?next?=?document.getElementById('next');
	var?index?=?1;
	
	
	function?showButton(){
		buttons[index-1].className?=?'on';
	}
		
	function?animate(offset){
		var?newLeft?=?parseInt(photos.style.left)?+?offset;
		photos.style.left?=?newLeft?+?'px';
		if(newLeft?>?-600){
			photos.style.left?=?-3000?+?'px';
		}
		if(newLeft?<?-3000){
			photos.style.left?=?-600?+?'px';
		}
	}
	
	next.onclick?=?function(){
		index?+=?1;
		showButton();
		animate(-600);
		
	}
	prev.onclick?=?function(){
		index?-=?1;
		
		animate(600);
		showButton();
	}
}

就是加上圓點的函數后開始出錯的。。。