// 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 : "") +
      ((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));
}

function firstTimeInSession(AName)
{
  AName = 'sft_' + AName;
  var firstTime = !getCookie(AName, 1);
  if (firstTime)
    setCookie(AName, 1);
  return firstTime;
}

function getPlatformInfoArray()
{
  return {
    'dc': document.defaultCharset,
    'l':   navigator.language,
    'bl':  navigator.browserLanguage,
    'sl':  navigator.systemLanguage,
    'ul':  navigator.userLanguage,

    'sx': screen.width,
    'sy': screen.height,
    'sc': screen.colorDepth
    }
}

function arrayToHTMLAttributesSimple(AArray, ATagName)
{
  var result = '';
  for (var i in AArray)
    result += (result ? ' ' : '') + i + '="' + (AArray[i] ? AArray[i] : '') + '"';
  if (ATagName)
    result = '<' + ATagName + (result ? ' ' + result : '') + '>';
  return result;
}

function logPlatformInfo()
{
  setCookie('pi', arrayToHTMLAttributesSimple(getPlatformInfoArray(), 'pi'));
}