AJAX后退按钮实现：它们如何工作？

If the common plugins for fixing AJAX’s back/forward breakage use a similar method and if not,what methods do they use?

他们同时使用民意调查和hashchange事件.

What are the pros. and cons. of the polling method,as well as any of the alternative methods.

>轮询优点：并非所有浏览器都支持hashchange,因此它是跨浏览器的
>投票的缺点：在性能方面更昂贵

Could I implement a simple version of these methods that will accomplish my goals? (say under 150 lines).

如果您只为5个人编写应用程序,也可以强制他们使用支持hashchange事件的现代浏览器.然后你可以只用2-3行编写哈希变化检测:)

window.onhashchange = function(event) {
    var url = event.newURL;
    // do something with new url
};

Is it worth it to do it myself? Am I going to learn anything valuable if I implement this? Will my (in theory) simpler version really be that much less code than a comprehensive plugin?

是的,见上文.你可以用很少的代码编写一个更好的实现.例如,Rails使用router向控制器分派请求.路线定义如下：

"/signup"           -> (UsersController,new)
"/user/(id)/photos" -> (PhotosController,index)

您可以定义自己的路由API以在JavaScript中注册路由及其处理函数/对象,并且比现有插件可以做更多更酷的事情,仅限于您的想象力:)