To reduce the battery life used by Chrome, the Google Chromium team is currently experimenting with limiting the frequency of power-consuming JavaScript timers. In a document titled "Limit JavaScript Timers to Reduce Battery Use in Background Tabs," the Chromium team explains how JavaScript timers are often misused by developers, saying, "We use Devtools to inspect the work performed by popular sites in the background. We have found that a lot of work has been done using JavaScript timers. Also, we found that the work done with these Javascript timers was often not useful to the user when the page was in the background (for example, checking if the scroll position has changed and reporting logs, analyzing ad interactions). "The Chromium team's experiments began after speculating that reducing the amount of wakeup times for JavaScript timers in background pages could extend battery life without harming the Chrome user experience.
JavaScript timers
Currently, background page wakeups in Chrome are limited to one wakeup call per second and around one percent of CPU usage. However, to improve battery life, the Chromium team ran experiments where these alarm clocks were limited to one per minute. They ran an experiment in Chrome with 36 background tabs and on: empty foreground tab, as well as a second experiment with 36 background tabs and YouTube in the foreground while playing a video in full screen to test their hypothesis. In both experiments, the background tabs included popular sites like Twitter, Gmail, Amazon, and Best Buy. For their tests, the Chromium team used a 2018 MacBook Pro and measured the time it took to drain the device's battery in full Chrome, limited Chrome, and Safari 13.1. Even when acceleration was turned on in Chrome, the device's battery drained faster than when testing with Safari. However, with throttling enabled, Chrome was much closer to Safari in terms of battery life impact than before. During the team's YouTube tests, throttling JavaScript timers dramatically extended the MacBook's battery life by nearly 36 minutes, or around 13%. End users are always looking to extend the battery life of their devices, and the Google Chromium team has found a way to do this without compromising the Chrome user experience. via ZDNet