function button_on ( imgId )
{

gg_on = new Image ( );
gg_off = new Image ( );

gg_on.src = "images/gg_on.gif";
gg_off.src = "images/gg_off.gif";


  if ( document.images )
  {
    butOn = eval ( imgId + "_on.src" );
    document.getElementById(imgId).src = butOn;
  }
}

function button_off ( imgId )
{

gg_on = new Image ( );
gg_off = new Image ( );

gg_on.src = "images/gg_on.gif";
gg_off.src = "images/gg_off.gif";


  if ( document.images )
  {
    butOff = eval ( imgId + "_off.src" );
    document.getElementById(imgId).src = butOff;
  }
}