if (document.images) {
    menu01_off       = new Image();
    menu01_off.src   = "images/menu01_off.jpg" ;
    menu03_off       = new Image();
    menu03_off.src   = "images/menu03_off.jpg" ;
    menu05_off       = new Image();
    menu05_off.src   = "images/menu05_off.jpg" ;
    menu07_off       = new Image();
    menu07_off.src   = "images/menu07_off.jpg" ;
    menu09_off       = new Image();
    menu09_off.src   = "images/menu09_off.jpg" ;

    menu01_on       = new Image();
    menu01_on.src   = "images/menu01_on.jpg" ;
    menu03_on       = new Image();
    menu03_on.src   = "images/menu03_on.jpg" ;
    menu05_on       = new Image();
    menu05_on.src   = "images/menu05_on.jpg" ;
    menu07_on       = new Image();
    menu07_on.src   = "images/menu07_on.jpg" ;
    menu09_on       = new Image();
    menu09_on.src   = "images/menu09_on.jpg" ;
}
function buttondown( buttonname )
{
    if (document.images) {
      document[ buttonname ].src = eval( buttonname + "_on.src" );
    }
}
function buttonup ( buttonname )
{
    if (document.images) {
      document[ buttonname ].src = eval( buttonname + "_off.src" );
    }
}

function xtoggle(id) {
   var e = document.getElementById(id);
   if(e.style.display == 'block')
      e.style.display = 'none';
   else
      e.style.display = 'block';
}