<!-- Début script rollover sur les images du menu horizontal -->
if ( document.images )
{
img_01_on = new Image ( );
img_01_off = new Image ( );
img_01_on.src = "_lib_medias/img_site/img_menu_01_on.png";
img_01_off.src = "_lib_medias/img_site/img_menu_01_off.png";
}

{
img_02_on = new Image ( );
img_02_off = new Image ( );
img_02_on.src = "_lib_medias/img_site/img_menu_02_on.png";
img_02_off.src = "_lib_medias/img_site/img_menu_02_off.png";
}

{
img_03_on = new Image ( );
img_03_off = new Image ( );
img_03_on.src = "_lib_medias/img_site/img_menu_03_on.png";
img_03_off.src = "_lib_medias/img_site/img_menu_03_off.png";
}

{
img_04_on = new Image ( );
img_04_off = new Image ( );
img_04_on.src = "_lib_medias/img_site/img_menu_04_on.png";
img_04_off.src = "_lib_medias/img_site/img_menu_04_off.png";
}


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

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

<!-- Fin du script -->