The browser update will block some specific applications of Flash, namely behind-the-scenes operations like page analytics, the company explained in a blog post. These are in fact claimed to account for over 90 percent of Flash on the Web, bogging down the performance of sites when compared with Google's preferred HTML5 format.
Chrome 55 — targeted for December — will default to HTML5 automatically, unless a website only works with Flash. Even then people will be prompted to enable the plugin on their first visit.
Google said it is still working with Adobe to optimize Flash, but it has also been gradually veering away from the format, for instance switching to HTML5 video on YouTube in January 2015. The company will block Flash ads entirely starting at the beginning of 2017, and Chrome already pauses less essential content automatically.
Flash has been derided not just for affecting speed and battery life but for being a major security risk, since it has regularly come under siege by hackers.
Apple is adopting a similar strategy with Safari 10, launching alongside macOS Sierra. The browser will not only default to HTML5 and require manual Flash activation, but display messages suggesting the plugin isn't installed even when it is.