function NuevaVentana(tolink,nombre,w,_h,scroll){
if (_h==-1) {
    var h=screen.height-80;
}else{
	var h=_h;}


    var winl = (screen.width - w) / 2;

   var wint = (screen.height - h) / 2;
   var winprops ="height="+h+",width="+w+",top="+wint+",left="+winl+",scrollbars=" +scroll 
   if (scroll==1) {winprops=winprops+ ",resizable,status";}
   var win = window.open(tolink, nombre, winprops);
   if (parseInt(navigator.appVersion) >= 4) 
   { 
   win.focus(); 
}
}

function CerrarVentana(){
window.close();
}