Google is developing a new cache for Chrome (via CNET)that should make some page loads extremely fast. The only catch? They’ll have to be pages you’ve already seen and are revisiting after hitting the browser’s back button.
Chrome already caches the files that make up a page, so revisiting a page in most circumstances shouldn’t force the browser to retrieve the images, JavaScripts, and CSS that are used to build the page. But currently, the browser has to re-parse the HTML and re-build the page’s programmatic representation, uncompress the images, re-execute all the JavaScript, reapply all the stylesheets, and so on. It’s just the networking step that gets skipped.
The new bfcache (for “back/forward cache”) changes that: it lets the browser capture the entire state of a running page—including scripts that are in the middle of execution, the rendered images, and even the scroll position—and reload that state later. With bfcache, rather than having to reload the page from scratch, the page will look as if it was paused when you click a link to a new page and subsequently resumed when you hit back.