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