function menushow(menu){
    var menuID=document.getElementById('menu'+menu);
    var subID=document.getElementById('sub'+menu);
    if(menuID.className=='0'){
      subID.style.display='block';
      menuID.className='1';
    }else{
      subID.style.display='none';
      menuID.className='0';
    }
  }

if(document.images) {
 var imgs = new Array();
 imgs[0] = new Image();  imgs[0].src = "images/opsmmrk2.gif";
 imgs[1] = new Image();  imgs[1].src = "images/opsmmrk1.gif";
}

function chgimg(id, imgname) {
 if(document.images) {
  if(imgs[imgname]) {
    document.images[id].src = imgs[imgname].src;
  }
  else {
    document.images[id].src = imgname;
  }
 }
}