javascript增加、获取和删除Cookie

/* *设置Cookie  * * name:cookie所对应的键 * value:cookie所对应的值 * expires:cookie所对应的有效时间 * path:指定可访问cookie的路径 * domain:指定可访问cookie的主机名 * secure:安全性 */function setCookie (name,value,expires,path,domain,secure) {        //cookie键值对     var str = name + "=" + escape(value);    //设置cookie的有效期,以小时为单位    if(expires > 0){                                       var date = new Date();        var ms = expires * 3600 * 1000;        date.setTime(date.getTime() + ms);        str += "; expires=" + date.toGMTString();    }    if(path){        str += "; path=" + path;    }    if(domain){        str += "; domain=" + domain;    }    if(secure){        str += "; secure";    }    document.cookie = str;}/* *获得Cookie  * *cookie_name:cookie的键 */function getCookie(cookie_name)  {         var value = null;    var allcookies = document.cookie;      var cookie_pos = allcookies.indexOf(cookie_name);      // 如果找到了索引，就代表cookie存在，      // 反之，就说明不存在。      if (cookie_pos != -1)      {          // 把cookie_pos放在值的开始，只要给值加1即可。          cookie_pos += cookie_name.length + 1;          var cookie_end = allcookies.indexOf(";", cookie_pos);          if (cookie_end == -1)          {               cookie_end = allcookies.length;          }          value = unescape(allcookies.substring(cookie_pos, cookie_end));      }      return value;  } /* *删除Cookie  * *cookie_name:cookie的键 */function delCookie(cookie_name){    var exp = new Date();    exp.setTime(exp.getTime() - 1);    var value = getCookie(cookie_name);    if(value){        document.cookie= cookie_name + "=" + value + ";expires=" + exp.toGMTString();    }}