var subs_array = new Array("sub1","sub2","sub3");// Put the id's of your hidden divs in this array
  
  function displaySubs(the_sub){
           if (document.getElementById(the_sub).style.display==""){
             document.getElementById(the_sub).style.display = "none";return
    }
    for (i=0;i<subs_array.length;i++){
             var my_sub = document.getElementById(subs_array[i]);
             my_sub.style.display = "none";
           }
    document.getElementById(the_sub).style.display = "";
  }