scrollList=new Array();

if (document.getElementById) {

	function registraScroll(idAbajo, idArriba, div, velAbajo, velArriba){
		if(scrollList[idAbajo]==null) scrollList[idAbajo]=new Array();
		if(scrollList[idArriba]==null) scrollList[idArriba]=new Array();
		scrollList[idAbajo].push(new Array(div, velAbajo));
		scrollList[idArriba].push(new Array(div, velArriba));
	}

	function initScroll(){
		for(key in scrollList){
			var elemento=document.getElementById(key);
			elemento.onmouseover=playScroll;
			elemento.onmouseout=stopScroll;
			elemento.onmousedown = function() { dobleVel(); return false; }
			elemento.onmouseup= function() { simpleVel(); return false; }
			elemento.onclick= function() { return false; }
		}
	}

	function dobleVel(){
		for(key in scrollDivs){
			velDivs[key]=2*velDivs[key];
		}
	}

	function simpleVel(){
		for(key in scrollDivs){
			velDivs[key]=velDivs[key]/2;
		}
	}
	
	function playScroll(){
		scrollDivs=new Array();
		velDivs=new Array();
		for(key in scrollList[this.id]){
			scrollDivs.push(document.getElementById(scrollList[this.id][key][0]));
			velDivs.push(scrollList[this.id][key][1]);
		}   
		itvScroll=setInterval('scrollNow()', 50);
	}

	function stopScroll(){
		clearInterval(itvScroll);
	}

	function scrollNow(){
		for(key in scrollDivs){
			var despActual=scrollDivs[key].scrollTop;
			var newDesp=despActual+velDivs[key];
			scrollDivs[key].scrollTop=newDesp; 
		}
	}

	addLoadEvent(initScroll);

}