function getCookie(name) {
   var start = document.cookie.indexOf(name+"=");
   var len = start+name.length+1;
   if ((!start) && (name != document.cookie.substring(0,name.length))) return null;
   if (start == -1) return null;
   var end = document.cookie.indexOf(";",len);
   if (end == -1) end = document.cookie.length;
   return unescape(document.cookie.substring(len,end));
}

function setCookie(name,value,expires,path,domain,secure) {
    var cookieString = name + "=" +escape(value) +
       ( (expires) ? ";expires=" + expires.toGMTString() : "") +
       ( (path) ? ";path=" + path : "") +
       ( (domain) ? ";domain=" + domain : "") +
       ( (secure) ? ";secure" : "");
    document.cookie = cookieString;
}

function deleteCookie(name,path,domain) {
   if (Get_Cookie(name)) document.cookie = name + "=" +
      ( (path) ? ";path=" + path : "") +
      ( (domain) ? ";domain=" + domain : "") +
      ";expires=Thu, 01-Jan-70 00:00:01 GMT";
} 

/**
  * 取得指定过期日期
  * @param minutes　正数时，表明自当前时间若干分钟后过期,为负数则相反。
  */
function expireDate(minutes)
{
	var today = new Date();
	var cookie_expire_date = new Date(today.getTime() + (minutes * 60 * 1000)); 
	return cookie_expire_date;
}