var curr=0;
var int_next;
var noPic;
var unvaiPic;
var arr= new Array();
var delay=6000000;
var container="mainImg";
var bigPic="";

function enlarge(pic){
	//alert(pic.src+"##"+unvaiPic +"  -> "+pic.src.indexOf("unpic.gif"));
	
	if(pic.src.indexOf(noPic.substring(noPic.lastIndexOf('/'+1)))!=-1){
		document.getElementById(container).src= noPic;
	}
	else if(pic.src.indexOf(unvaiPic.substring(unvaiPic.lastIndexOf('/')+1))!=-1){
		document.getElementById(container).src= unvaiPic;
	}
	else{
		document.getElementById(container).src= bigPic+pic.src.substring(pic.src.lastIndexOf('/')+1);
	}
}


function isInt(num){
	aux= parseInt(num);
	if(aux==num){
		return true;	
	}
	else{
		return false;
	}
}


function initShow(){
	show();
	if(arr.length==0){
		document.getElementById(container).src=unvaiPic;
	}else{
		enlarge(document.getElementById('pic0'));
		
		}
}

function prev(){
	clearTimeout(int_next);
	//alert(curr);
	var middle=arr.length/4;
	if((curr-1)<0 && !isInt(middle)){
		curr=arr.length-1;
	}
	else{
		curr=((curr-4)<0)?arr.length-4:curr-4;
	}
	show();
}

function next(){
	clearTimeout(int_next);
	curr=((curr+4)>=arr.length)?0:curr+4;
	show();
}

function show(){
	for(x=0; x<4; x++){
		if((curr+x)<arr.length){
			if(curr>=0){
				var oPic=document.getElementById('pic'+x);
				oPic.style.visibility="visible";
				//oPic.filters[0].Apply();
						oPic.src=(arr[curr+x]!="")?arr[curr+x]:noPic;
				//oPic.filters[0].Play();
			}
		}
		else if(unvaiPic){
			var oPic=document.getElementById('pic'+x);
			oPic.style.visibility="visible";
			//oPic.filters[0].Apply();
					oPic.src=unvaiPic;	
			//oPic.filters[0].Play();
		}
		else{
			var oPic=document.getElementById('pic'+x);
				oPic.style.visibility="hidden";
		}
	}
	int_next=setTimeout(next,delay);
}