// JavaScript Document
window.onload=hideAllMenus;
document.onclick=hideAllMenus; 
  
function showMenu(menuNumber) { 
  hideAllMenus(); 
  document.getElementById('s'+menuNumber).style.visibility='visible'; 
} 
  
function hideAllMenus() { 
  for (counter=1; counter<=4; counter++) { 
  document.getElementById('s'+counter).style.visibility='hidden'; 
  } 
}