/*
   name - name of the cookie
   value - value of the cookie
   [expires] - string of expiration date of the cookie
     (defaults to end of current session)
   [path] - path for which the cookie is valid
     (defaults to path of calling document)
   [domain] - domain for which the cookie is valid
     (defaults to domain of calling document)
   [secure] - Boolean value indicating if the cookie transmission requires
     a secure transmission
   * an argument defaults when it is assigned null as a placeholder
   * a null placeholder is not required for trailing omitted arguments
*/

function setCookie(name, value, expires, path, domain, secure) {
  var curCookie = name + "=" + escape(value) +
      ((expires) ? "; expires=" + expires : "") +
      ((path) ? "; path=" + path : "") +
      ((domain) ? "; domain=" + domain : "") +
      ((secure) ? "; secure" : "");
  document.cookie = curCookie;
}


/*
  name - name of the desired cookie
  return string containing value of specified cookie or null
  if cookie does not exist
*/

function getCookie(name) {
  // document.write("<br>name="+name);
  var dc = document.cookie;
  var prefix = name + "=";
  var begin = dc.indexOf("; " + prefix);
  if (begin == -1) {
    begin = dc.indexOf(prefix);
    if (begin != 0) 
      return null;
  } else
    begin += 2;
  var end = dc.indexOf(";", begin);
  if (end == -1)
    end = dc.length;
  return unescape(dc.substring(begin + prefix.length, end));
}


/*
   name - name of the cookie
   [path] - path of the cookie (must be same as path used to create cookie)
   [domain] - domain of the cookie (must be same as domain used to
     create cookie)
   path and domain default if assigned null or omitted if no explicit
     argument proceeds
*/

function deleteCookie(name, path, domain) {
  if (getCookie(name)) {
    document.cookie = name + "=" +
    ((path) ? "; path=" + path : "") +
    ((domain) ? "; domain=" + domain : "") +
    "; expires=Thu, 01-Jan-70 00:00:01 GMT";
  }
}

/*
  name <cis>-- name of the desired variable 
  return string containing value <cs> of specified name <cis>
         or null if cookie name not exist
*/
function getValueFromUrl(name)
{
  var url = '' + this.location;
  var idx  = url.indexOf('?');
  if(idx==-1)
	return null;
  var query = "&" + url.substring(idx+1);
  var qs = query.toLowerCase();
  var key = "&" + name.toLowerCase() + "=";
  var begin = qs.indexOf(key);
  if(begin==-1)
	return null;
  else
    begin += key.length;
  var end = qs.indexOf("&", begin);
  if (end == -1)
    end = query.length;
  return unescape(query.substring(begin, end));
}