var xassoc = { "client"    : "client",
               "operator"  : "operator",
               "cpanel"    : "cpanel" };

function openDiv(divName)
{      
   for(prop in xassoc)
   {
      document.getElementById(prop).style.display = 'none';
   }
   
   var eid = document.getElementById(divName);
   eid.style.display = 'block';   
}