function abrirVentana(nombre,w,h){
	   var origX = Math.round(( screen.availWidth - w ) / 2 );
	   var origY = Math.round(( screen.availHeight - h ) / 2 );
	   ventana = window.open(nombre,"ventana","directories=no,scrollbars=yes,status=no,toolbar=no,menubar=no,location=no,screenX="+origX+",screenY="+origY+",innerHeight="+h+",innerWidth="+w+",width="+w+",height="+h);
         ventana.resizeTo(w,h);
         ventana.moveTo(origX,origY);
   }