NS4 = (document.layers) ? 1 : 0; 
 IE4 = (document.all) ? 1 : 0; 
 NS6 = (document.getElementById) ? 1 : 0; 
  
 currentParam  = false;
 
 
function show(menu) { 
     currentParam = true;
     if(NS4) document.layers[menu].display = "show"; 
     if(IE4) document.all(menu).style.display = "block"; 
     if(NS6) document.getElementById(menu).style.display = "block"; 
 } 
 function hide(menu) { 
     currentParam = false; 
     if(NS4) document.layers[menu].display = "none"; 
     if(NS6) document.getElementById(menu).style.display = "none"; 
     if(IE4) document.all(menu).style.display = "none"; 
 } 
  
 function showOrHide(menu) { 
     if (currentParam == true) { 
         hide(menu) 
     } else { 
         show(menu) 
     } 
 }