var mac = (navigator.appVersion.indexOf("Mac") >0 )? true : false;

function getPos(w,h)
{
	var nW = (mac && document.all)? w-16 : w;
	var nH = h;
	var list = {
		x : Math.round((screen.availWidth/2) - (nW/2)),
		y : Math.round((screen.availHeight/2) - (nH/2)),
		w : nW,
		h : nH		
	}
	return list;
}

function openWin(pag,w,h,s)
{
	if(w == null) w = 650;
	if(h == null) h = 500;
	if(s == null) s = "yes";
	var pos = getPos(w,h);
	var w_pop = window.open(pag, "new_window","width=" + pos.w + ", height=" + pos.h + ", top=" + pos.y + ", left=" + pos.x + ", scrollbars=" + s);
	var tmr = setTimeout(function()
	{
		if(!w_pop) alert("Por favor, activa la opción de abrir ventanas emergentes de tu navegador para imprimir la información. Gracias.");
	}, 1000);
}