function toggleNav(num) {
  var state = (typeof(arguments[1])!='undefined') ? arguments[1] : null;
  var ul = document.getElementById('nav-left'+num);
  var sq = document.getElementById('toggleSquare'+num);
  if ( !(sq && ul && ul.className=='nav-left') ) return;
  
  if ( (state!='closed') && ((ul.style.display=='none')||(state=='open')) ) {
    ul.style.display='block';
    sq.style.backgroundPosition='0px 0px';
  } else {
    ul.style.display='none';
    sq.style.backgroundPosition='-9px 0px';
  }
  // save current state in a cookie
  putNavStates();
} 

function getNavStates() {
  var rawCookie = readCookie('navstate');
  if (rawCookie==null) return false;
  
  
  var i = 0;
  var num = 0;
  var ul;
  while (i < rawCookie.length) {
    var isShowing = (rawCookie.charAt(i)=='y'); // true of false
    do {
      ul = document.getElementById('nav-left'+num);
      if (!ul) {return false;}
      num++;
    } while ( ul.className!='nav-left' );
    toggleNav( (num - 1), (isShowing ? 'open' : 'closed') );

    i++;
  }
  return true;
}

// This function saves the current nav states to a cookie
function putNavStates() {
  var rawCookie = '';
  
  var num=0;
  var ul = document.getElementById('nav-left0');
  while (ul) {
    if (ul.className=='nav-left') {
      if (ul.style.display=='none') {
        rawCookie += 'n';
      } else {
        rawCookie += 'y';
      }
    }
    num++;
    ul = document.getElementById('nav-left'+num);
  }
  
  createCookie('navstate', rawCookie, 7);
}