Chrome could get way faster at loading some websites in 2020 with a feature called bfcache

By Stephen Shankland

Chrome is going to get a big speed boost -- at least for web pages you've recently visited.

A Chrome lapel pin

A Chrome lapel pin

Stephen Shankland/CNET

With a feature called bfcache -- backward-forward cache -- Google's web browser will store a website's state as you navigate to a new page. If you then go back to that page, Chrome will reconstitute it rapidly instead of having to reconstruct it from scratch. Then, if you retrace your steps forward again, Chrome will likewise rapidly pull that web page out of its memory cache.

The speed boost doesn't help when visiting new websites. But this kind of navigation is very common: Going back accounts for 19 percent of pages viewed on Chrome for Android and 10 percent on Chrome for personal computers, Google said. With bfcache, that becomes "extremely fast."

Every incremental browser speedup is significant -- not just for you and for Chrome, but for the web overall. Especially on phones, apps are a dominant way we tap into online services. Making the web a bit faster means developers can rely more on the neutral technology foundation of the web instead of apps that must play by the rules of Apple's iOS and Google's Android. Maybe you're happy with your apps, but the web offers a way to get information and interact without apps' cumbersome download and installation.

Apple's Safari browser and Mozilla's Firefox already support similar caching technology. So Chrome is catching up here.

The tricky part for Chrome is rewriting some core parts of the browser to protect privacy and security. That's because Chrome has to make sure it really does stop web-based JavaScript programs from running even though it's hanging onto them in memory, said Addy Osmani, an engineering manager on the Chrome team.

"Running JavaScript on pages which are not there from the user's perspective is a big potential privacy problem, which is why we are going to change Chrome's architecture to ensure that this doesn't happen," he said Monday.

Google hopes to test bfcache in 2019 and build it into Chrome in 2020, he said.

Saving the state of web pages for possible later use will consume memory -- a sticking point already for browsers. Google is still trying to figure out the best rules for deciding which pages to keep around and when to dump them from memory, Osmani said.

The feature could help with other situations, too, he added. One is better performance for tabs that Chrome needs to pause while they're in the background, particularly on mobile devices. That saves memory, but today paused pages can be frustrating when you return to them and they're slow to reload.