JS使用 popstate 事件監聽物理返回鍵

      pushHistory();
        window.addEventListener("popstate", function (e) {
            if (orderid != "") {
                window.location.href = "/wap/self/orderinfo.aspx?id=" + orderid; //此處可改為任意地址
            } else {
                history.back();
            }
        }, false);
        function pushHistory() {
            var state = {
                title: "title",
                url: "#"
            };
            window.history.pushState(state, "title", "#");
        }