js中cookie的读取、添加和修改

        //写cookies
          function setCookie(name, value) {
              var Days = 30;
              var exp = new Date();
              exp.setTime(exp.getTime() + Days * 24 * 60 * 60 * 1000);
              document.cookie = name + "=" + parseInt(value) + ";expires=" + exp.toGMTString();
          }
          //读取cookies
          function getCookie(name) {
              var arr, reg = new RegExp("(^| )" + name + "=([^;]*)(;|$)");
              if (arr = document.cookie.match(reg))
                  return unescape(arr[2]);
              else
                  return null;

          }

//调用

 var enter_num = "xzz_isdown"; //添加cookie

var b_value = getCookie(enter_num);//获取cookie

setCookie(enter_num, 1);//修改cookie