JavaScriptでCookieを扱う

// data・・・cookieに格納する連想配列
// period・・・cookieの有効期間(日)
var setCookie = (function(){
 return function(data, period) {
  var cookies = '';
  for (var key in data) {
   cookies += key + '=' + encodeURIComponent(data[key]) + '; ';
  }

  var expire = new Date();
  expire.setTime( expire.getTime() + 1000 * 3600 * 24 * period);
  expire.toUTCString();

  cookies += 'expires=' + expire+';';

  document.cookie = cookies;
 };
})();

var getCookie = (function(){
 return function() {
  var result = [];
  var cookies = document.cookie;

  if(cookies != ''){
   var cookieArray = cookies.split(';');
   for(var i = 0; i < cookieArray.length; i++){
    var cookie = cookieArray[i].split('=');
    result[cookie[0]] = decodeURIComponent(cookie[1]);
   }
  }
  return result;
 };
})();