function abrir(x,y,z,t) {
     if (navigator.appName == 'Netscape') {
     	y = 20 + y;
     	z = 20 + z;
     	ven = open(x+".htm",x,"width="+y+",height="+z+",status=no,toolbar=no,menubar=no,scrollbars="+t);
     } else {
     	ven = open(x+".htm",x,"width="+y+",height="+z+",status=no,toolbar=no,menubar=no,scrollbars="+t);
     }
}