function GetCookie (name)
{
    var arg  = name + "=";
    var alen = arg.length;
    var clen = document.cookie.length;
    var i    = 0;
    while (i < clen)
    {
        var j = i + alen;
        if (document.cookie.substring(i, j) == arg)
          return getCookieVal (j);
        i = document.cookie.indexOf(" ", i) + 1;
        if (i == 0) break;
    }
    return null;
}

function getCookieVal( offset )
{
    var endstr = document.cookie.indexOf (";", offset);

    if (endstr == -1)
        endstr = document.cookie.length;
    return unescape(document.cookie.substring(offset, endstr));
}

function SetCookie( name, value )
{
    var argv    = SetCookie.arguments;
    var argc    = SetCookie.arguments.length;
    var expires = (argc > 2) ? argv[2] : null;
    var path    = (argc > 3) ? argv[3] : null;
    var domain  = (argc > 4) ? argv[4] : null;
    var secure  = (argc > 5) ? argv[5] : false;

    document.cookie =
        name + "=" + escape (value) +
        ((expires == null) ? "" : ("; expires=" + expires.toGMTString())) +
        ((path == null) ? "" : ("; path=" + path)) +
        ((domain == null) ? "" : ("; domain=" + domain)) +
        ((secure == true) ? "; secure" : "");
}

function DeleteCookie (name)
{
    var exp  = new Date();
    var cval = GetCookie (name);

    exp.setTime (exp.getTime() - 1);  // This cookie is history
    document.cookie = name + "=" + cval + "; expires=" + exp.toGMTString();
}

function extractCookieValue(val) {

  if ((endOfCookie = document.cookie.indexOf(";", val)) == -1) {
      endOfCookie = document.cookie.length;
  }
  return unescape(document.cookie.substring(val, endOfCookie));
}

// чтение ключа
function ReadCookie(cookiename) {
  var numOfCookies = document.cookie.length;
  var nameOfCookie = cookiename + "=";
  var cookieLen = nameOfCookie.length;
  var x = 0 ;
  while (x <= numOfCookies) {
    var y = (x + cookieLen);
    if (document.cookie.substring(x, y) == nameOfCookie)
      return (extractCookieValue(y));
      x = document.cookie.indexOf(" ", x) + 1;
    if (x == 0)
      break;
  }
  return "";
}

// создание ключа
// для удаления - expiredays = -1
function createCookie(name, value, expiredays)
{
var todayDate = new Date();
todayDate.setDate(todayDate.getDate() + expiredays);
document.cookie = name +
                  "=" +
                  value +
                  "; expires=" +
    todayDate.toGMTString() +
    ";"
}