/*
   name - name of the cookie
   value - value of the cookie
   [expires] - 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.toGMTString() : "") +
      ((path) ? "; 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) {
	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 = document.cookie.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";
  	}
}