function getCookie(name)// 使用名称参数取得Cookie值, null表示Cookie不存在
{ var strCookies = document.cookie;
  var cookieName = name + "=";  // Cookie名称
  var valueBegin, valueEnd, value;
  valueBegin = strCookies.indexOf(cookieName);// 寻找是否有此Cookie名称
  if (valueBegin == -1) return null;  // 没有此Cookie
  valueEnd = strCookies.indexOf(";", valueBegin);// 取得值的结尾位置
  if (valueEnd == -1)
      valueEnd = strCookies.length;  // 最後一个Cookie
  value = strCookies.substring(valueBegin+cookieName.length,valueEnd);// 取得Cookie值
  return value;
}//end function getCookie

function saveCookie(name, value, expires, path, domain, secure)// 保存Cookie
{ var strCookie = name + "=" + value;
  if (expires){// 计算Cookie的期限, 参数为天数
     var curTime = new Date();
     curTime.setTime(curTime.getTime() + expires*24*60*60*1000);
     strCookie += "; expires=" + curTime.toGMTString();
  }
  strCookie +=  (path) ? "; path=" + path : ""; // Cookie的路径
  strCookie +=  (domain) ? "; domain=" + domain : "";// Cookie的Domain
  strCookie +=  (secure) ? "; secure" : "";// 是否需要保密传送,为一个布尔值
  document.cookie = strCookie;
}

function checkCookieExist(name)// 检查Cookie是否存在
{ if (getCookie(name))
	return true;
  else
	return false;
}//end function checkCookieExist

function deleteCookie(name, path, domain)// 删除Cookie
{ var strCookie;
  if (checkCookieExist(name)){// 设置Cookie的期限为己过期
	strCookie = name + "="; 
	strCookie += (path) ? "; path=" + path : "";
	strCookie += (domain) ? "; domain=" + domain : "";
	strCookie += "; expires=Thu, 01-Jan-70 00:00:01 GMT";
	document.cookie = strCookie;
  }//end if
}//end function deleteCookie