function deleteCookie(name, path, domain) {
  if (getCookie(name)) {
    document.cookie = name + "=" +
    ((path) ? "; path=" + path : "") +
    ((domain) ? "; domain=" + domain : "") +
    "; expires=Thu, 01-Jan-1999 00:00:01 GMT";
  }
}

function toggleLayer( whichLayer )
{  
var elem, vis;  
if( document.getElementById ) // this is the way the standards work  
elem = document.getElementById( whichLayer );  
else if( document.all ) // this is the way old msie versions work    
elem = document.all[whichLayer];  
else if( document.layers ) // this is the way nn4 works   
elem = document.layers[whichLayer];
vis = elem.style;  // if the style.display value is blank we try to figure it out here 
if(vis.display==''&&elem.offsetWidth!=undefined&&elem.offsetHeight!=undefined)   
vis.display = (elem.offsetWidth!=0&&elem.offsetHeight!=0)?'block':'none';
vis.display = (vis.display==''||vis.display=='block')?'none':'block';
writePersistentCookie (whichLayer, vis.display, "months", 1)
}


//Get cookie routine 
function get_cookie(Name) {
  var search = Name + "="
  var returnvalue = "";
  if (document.cookie.length > 0) {
    offset = document.cookie.indexOf(search)
    // if cookie exists
    if (offset != -1) { 
      offset += search.length
      // set index of beginning of value
      end = document.cookie.indexOf(";", offset);
      // set index of end of cookie value
      if (end == -1) end = document.cookie.length;
      returnvalue=unescape(document.cookie.substring(offset, end))
      }
   }
  return returnvalue;
}
function testPersistentCookie () {
  writePersistentCookie ("testPersistentCookie", "Enabled", "minutes", 1);
  if (getCookieValue ("testPersistentCookie")=="Enabled")
    return true  
  else 
    return false;
}

function setPersistentCookieTest () {  
  if (testPersistentCookie()) {
    var myName = document.getElementById('f4CookieName').value;
    var myValue = document.getElementById('f4CookieValue').value;
    var myPeriod = document.getElementById('f4TimePeriod').value;
    var myOffset = document.getElementById('f4TimeValue').value;
    writePersistentCookie (myName, myValue, myPeriod, myOffset);
    alert ("Persistent cookie written");
  }
  else
    alert ("Sorry - session cookies are currently disabled."); 
}

function writePersistentCookie (CookieName, CookieValue, periodType, offset) {

  var expireDate = new Date ();
  offset = offset / 1;
  
  var myPeriodType = periodType;
  switch (myPeriodType.toLowerCase()) {
    case "years": 
     var year = expireDate.getYear();     
     // Note some browsers give only the years since 1900, and some since 0.
     if (year < 1000) year = year + 1900;     
     expireDate.setYear(year + offset);
     break;
    case "months":
      expireDate.setMonth(expireDate.getMonth() + offset);
      break;
    case "days":
      expireDate.setDate(expireDate.getDate() + offset);
      break;
    case "hours":
      expireDate.setHours(expireDate.getHours() + offset);
      break;
    case "minutes":
      expireDate.setMinutes(expireDate.getMinutes() + offset);
      break;
    default:
      alert ("Invalid periodType parameter for writePersistentCookie()");
      break;
  } 
  
  document.cookie = escape(CookieName ) + "=" + escape(CookieValue) + "; expires=" + expireDate.toGMTString() + "; path=/";
}