Chris Peterson, Mozilla's technical program manager, tweeted on Tuesday that the video sharing site loads at a fifth of the speed on non-Chrome browsers due to its architecture.
YouTube page load is 5x slower in Firefox and Edge than in Chrome because YouTube's Polymer redesign relies on the deprecated Shadow DOM v0 API only implemented in Chrome. You can restore YouTube's faster pre-Polymer design with this Firefox extension: https://t.co/F5uEn3iMLR
Chris Peterson (@cpeterso) July 24, 2018
"YouTube's Polymer redesign relies on the deprecated Shadow DOM v0 API only implemented in Chrome," he wrote.
"YouTube serves a Shadow DOM polyfill to Firefox and Edge that is, unsurprisingly, slower than Chrome's native implementation. On my laptop, initial page load takes 5 seconds with the polyfill vs 1 without. Subsequent page navigation perf is comparable."
Peterson suggested fixes for both Firefox and Microsoft's Edge that revert YouTube to a previous version using add-ons.
He notes that YouTube "still serves the pre-Polymer design" to Microsoft's Internet Explorer 11, which launched in 2013 and has been replaced by Edge, and suggests that Google could have taken the same approach with Edge and Firefox.
Google did not respond to requests for comment.
Chrome is the most popular web browser and accounts for 59 percent of website usage, according to analytics firm StatCounter. Firefox accounts for 5 percent, while Edge has 2 percent.
On Tuesday, the latest version of Chrome expanded Google's fight against surveillance and security risks by showing a "not secure" warning for any HTTP website.