Please welcome YSlow for Chrome

Ever since YSlow for Firefox was first released, it has helped millions of developers analyze web pages and suggested ways for them to improve their websites' performance. YSlow ranks in the Top 25 for Best of 2 Billion Firefox Add-ons downloaded so far. We are very proud of where YSlow stands today and we continue to work hard to take it to the next level.

Today's another "Hello World!" moment for YSlow. We are very excited to announce the beta release of YSlow for Chrome. YSlow looks beautiful inside the Chrome browser.

Image of YSlow running on Yahoo! homepage seen within Chromeyslow_chrome

    Here are some of the feature highlights:

- You'll feel at home here. We kept the user experience consistent with YSlow for Firefox.
- Added the ability to detect post onload components, including for pages that prevent itself from being embedded and/or iframed. (experimental)
- Support for 3 main rulesets: Default YSlow V2, Classic V1, and Small Site or Blog as well as the ability to create new ones based on these 3.
- Offenders in CDN rule are now listed as domains only.
- Runs multiple YSlow instances (new windows). This feature is excellent for comparing YSlow results for different pages side-by-side as shown below.

Screenshot comparing Amazon and Yahoo! performance w/YSlowyslow_Compare-blog
Some caveats: As of today, the current version of Chrome does not provide access to its network panel. As a result, we have relied on Ajax calls to do most of the heavy lifting for us. Hence, some rules might be affected thus, fluctuating the grades a bit if you compare them with the Firefox version.

Special thanks to Marcel Duran, front-end engineering lead for the Exceptional Performance team, who has led all the development efforts for this next-generation YSlow. We would also like to thank Stoyan Stefanov, our YSlow alumnus, for his valuable technical guidance.

If you’re interested in learning some of the “behind-the-scenes” techniques used to build YSlow for Chrome, please join us for a presentation introducing next-gen YSlow on March 15th during the Velocity online conference.

Last but not least, since this is a beta release, so please voice your feedback, report bugs, or request features on the Yahoo! Group for Exceptional Performance.