/**
 * Read the JavaScript cookies tutorial at:
 *   http://www.netspade.com/articles/javascript/cookies.xml
 */

/**
 * Sets a Cookie with the given name and value.
 *
 * name       Name of the cookie
 * value      Value of the cookie
 * [expires]  Expiration date of the cookie (default: end of current session)
 * [path]     Path where the cookie is valid (default: path of calling document)
 * [domain]   Domain where the cookie is valid
 *              (default: domain of calling document)
 * [secure]   Boolean value indicating if the cookie transmission requires a
 *              secure transmission
 */
function setCookie(name, value, expires, path, domain, secure)
{
   var today = new Date();
   today.setTime( today.getTime() );
   // if the expires variable is set, make the correct expires time, the
   // current script below will set it for x number of days, to make it
   // for hours, delete * 24, for minutes, delete * 60 * 24
   if ( expires )
   {
      expires = expires * 1000 * 60 * 60 * 24;
   }
   //alert( 'today ' + today.toGMTString() );
   var expires_date = new Date( today.getTime() + (expires) );
   //alert('expires ' + expires_date.toGMTString());

    document.cookie= name + "=" + escape(value) +
        ((expires) ? "; expires=" + expires_date.toGMTString() : "") +
        ((path) ? "; path=" + path : "") +
        ((domain) ? "; domain=" + domain : "") +
        ((secure) ? "; secure" : "");
    //alert( unescape( document.cookie ) ); 
}

/**
 * Gets the value of the specified cookie.
 *
 * name  Name of the desired cookie.
 *
 * Returns a 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, end;
    
    //alert( "document.cookie = " + dc );
    
    if( !dc || ( begin = dc.indexOf( prefix ) ) < 0 )
    {
       return null;
    }
    
    if( ( end = dc.indexOf( ";", begin ) ) < 0 )
    {
        end = dc.length;
    }
    
    return unescape( dc.substring( begin + prefix.length, end ) );
}

/**
 * Deletes the specified cookie.
 *
 * 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)
 */
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"; 
   }      
}