var navegador = nav();

function nav() {
  var agent = navigator.userAgent
  if (agent.search(/MSIE/)!=-1) { return "MSIE"; }
  else if (agent.indexOf("Firefox")!=-1) { return "Firefox"; }
  else if (agent.indexOf("Safari")!=-1) { return "Safari"; }
  else if (agent.indexOf("Opera")!=-1)	{ return "Opera"; } 
  else { return "Other"; }
}

function init() {
        scrollActive = 0
        scrollContentShown = document.getElementById("lista")
		scrollLimitup = 0;
        scrollLimitdown =  (document.getElementById("lista").scrollHeight - document.getElementById("lista").offsetHeight);
		incremento = 5;
		velocidad = 50;
		vel=1;
		if (scrollLimitdown<0){
		  document.getElementById("btnUp").style.visibility="hidden";
		  document.getElementById("btnDown").style.visibility="hidden";
		}
}

function scroll(direction) {
    if (scrollActive) {
	  var top = scrollContentShown.scrollTop;
	  if (direction == "up" && top > scrollLimitup) {
	    var inc = (-1) * incremento
	    scrollContentShown.scrollTop += (inc*vel);
        setTimeout("scroll('up')",velocidad)}
	  else if (direction == "down" && top < scrollLimitdown) {
	    var inc = incremento
	    scrollContentShown.scrollTop += (inc*vel);
        setTimeout("scroll('down')",velocidad)}

	  if (top <= scrollLimitup)
	  { document.getElementById("btnUp").style.visibility='hidden'; } else { document.getElementById("btnUp").style.visibility='visible'; }
	  if (top >= scrollLimitdown) { document.getElementById("btnDown").style.visibility='hidden'; } else { document.getElementById("btnDown").style.visibility='visible'; }
   }
}
function findPos(obj) {
	var curleft = curtop = 0;
	if (obj.offsetParent) {
		curleft = obj.offsetLeft
		curtop = obj.offsetTop
		while (obj = obj.offsetParent) {
			curleft += obj.offsetLeft
			curtop += obj.offsetTop
		}
	}
	return [curleft,curtop];
}
function toggle(obj) {
	var el = document.getElementById(obj);
	if ( el.style.display != 'none' ) {
		el.style.display = 'none';
	}
	else {
		el.style.display = '';
	}
}