更新页面DOM后，如何修改浏览器缓存？

So far, I know that I can seperate static and dynamic content using AJAX, so if a blog post has a comment update, the article does not have to be redownloaded (it'd be 304), only the comments. Now, I'm thinking of persisting the fetched dynamic content so that next time, only new comments have to be requested. Is there any way to do this without relying on Flash/Gears/HTML5Storage or other plugins?So far, I know that I can seperate static and d