pushState顾名思义，意味着你要保存你的state的，不然浏览器也不知道后退之后的页面该长啥样
你需要将你页面的状态，传入history.pushState的第一个参数，标题传入第二个参数
然后你需要监听window的onpopstate事件，你绑定的state会在event对象上传给你

这段MDN的代码能说明问题：

window.onpopstate = function(event) {
  console.log("location: " + document.location + ", state: " + JSON.stringify(event.state));
};
history.pushState({page: 1}, "title 1", "?page=1");
history.pushState({page: 2}, "title 2", "?page=2");
history.replaceState({page: 3}, "title 3", "?page=3");
history.back(); // Logs "location: http://example.com/example.html?page=1, state: {"page":1}"
history.back(); // Logs "location: http://example.com/example.html, state: null
history.go(2);  // Logs "location: http://example.com/example.html?page=3, state: {"page":3}

https://developer.mozilla.org/en-US/docs/Web/Events/popstate