var boton="x";
agent=navigator.userAgent;
browser_version=2;
if (navigator.appVersion.substring(0,1) < "3")
  browser_version = 2; 
else 
  browser_version = 1; 

if (browser_version == 1){

	/// declaracion de botones
	f1on = new Image(129,19);
	f2on = new Image(129,19);
	f3on = new Image(129,19);
	f4on = new Image(129,19);
	f5on = new Image(129,19);
	f1on.src = "grafica/portada/botir2_port.gif";
	f2on.src = "grafica/portada/botexpansion2_port.gif";
	f3on.src = "grafica/portada/botirrupcion2_port.gif";
	f4on.src = "grafica/portada/botamerica2_port.gif";	
	f5on.src = "grafica/portada/botvisita2_port.gif";
	
	f1off = new Image(129,19);
	f2off = new Image(129,19);
	f3off = new Image(129,19);
	f4off = new Image(129,19);
	f5off = new Image(129,19);
	f1off.src = "grafica/portada/botir1_port.gif";
	f2off.src = "grafica/portada/botexpansion1_port.gif";
	f3off.src = "grafica/portada/botirrupcion1_port.gif";
	f4off.src = "grafica/portada/botamerica1_port.gif";	
	f5off.src = "grafica/portada/botvisita1_port.gif";
	// fin de declaracion de botones

}
function ImgAct(imgName)
{ if (browser_version == 1)
  { imgOn = eval(imgName + "on.src");
    document [imgName].src = imgOn;
  }
}
function ImgInact(imgName)
{ if (browser_version == 1)
  { if (boton !=imgName)
    { imgOff = eval(imgName + "off.src");
      document [imgName].src = imgOff;
    }
  }
}
function elegido(imgName)
{ if (browser_version == 1)
  { var aux=boton;
    boton=imgName
    if (aux !="x")
    { ImgInact(aux);
    }
  }
}