We’re pleased to share that three new W3C Web Performance Working Group specifications moved to W3C Candidate Recommendations. Accurately measuring the performance characteristics of Web applications is critical to making the Web faster. In addition, developers need the ability to effectively use the underlying hardware to improve the performance of their applications. Over the last two years, companies including Microsoft, Google, Mozilla, Intel, and Facebook have been working toward these goals through the working group. This is a great example of what’s possible when the industry and community come together through the W3C.
The Navigation Timing, Resource Timing, User Timing and Performance Timeline specifications help developers accurately measure Web application performance. The first three specifications provide developers with information related to the navigation of the document, resources on the page, and developer scripts, respectively. The Performance Timeline specification defines a unifying interface to retrieve this timing data. Prior to these API’s it was not possible for developers to accurately measure their site performance.
To ensure these performance metrics are measured in the most accurate way possibly, the High Resolution Time specification defines a sub-millisecond clock resolution. This interface not only benefits accurate measurements of performance metrics, but also allows better frame rate calculations and synchronization of animations or audio cues. For the first time developers can measure operations with sub-millisecond accuracy.
The Page Visibility, Timing control for script-based animations, and Efficient Script Yielding specifications help developers write more CPU- and power-efficient Web applications. The Page Visibility API allows for programmatically determining the current visibility state of the page. Developers can use this data to make better CPU- and power-efficiency decisions, e.g., throttling down activity when the page is in the background tab. The requestAnimationFrame API, from the Timing control for script-based animations specification, allows for creating more efficient JavaScript animations. Finally, the setImmediate API, from the Efficient Script Yielding specification, allows developers to efficiently yield control flow to the user agent and receive an immediate callback, efficiently leveraging the CPU.
In order to ensure Web developers only have to write code once and have it work interoperably in all browsers, the Working Group has worked diligently these last two years to standardize these APIs. The table below shows the maturity level of all the specifications currently being edited in the Working Group.
| Specification | Editor’s Draft | First Public Working Draft | Last Call | Last Call 2 | Candidate Rec | Proposed Rec | Rec |
|---|---|---|---|---|---|---|---|
| Navigation Timing | Sept 2010 | Oct 2010 | Jan 2011 | Feb 2011 | July 2012 | ||
| Resource Timing | Sept 2010 | May 2011 | June 2011 | May 2012 | |||
| User Timing | Oct 2010 | Aug 2011 | Aug 2011 | May 2012 | July 2012 | ||
| Performance Timeline | July 2011 | Aug 2011 | Aug 2011 | May 2012 | July 2012 | ||
| High Resolution Time | Mar 2012 | Mar 2012 | Mar 2012 | May 2012 | |||
| Page Visibility | Apr 2010 | June 2011 | July 2011 | July 2012 | |||
| Display Paint Notifications | May 2011 | June 2011 | Feb 2012 | ||||
| Efficient Script Yielding | June 2011 | ||||||
| Navigation Timing 2 (NEW) | Apr 2012 | May 2012 |
Table showing the status of W3C Web Performance Specifications
As of this month, the Navigation Timing specification has been published as a Proposed Recommendation (PR). This stage of standardization is the final step before a Web standard becomes an official W3C Recommendation. Additionally, this interface has been broadly adopted in browsers, including support since Internet Explorer 9, Chrome 6 and Firefox 7. The working group recently started incorporating feedback and working on Navigation Timing 2, the next version of the specification.
As of this month, User Timing, Performance Timeline and Page Visibility specifications have been published as a Candidate Recommendation (CR). This stage of standardization is prior to the PR stage and reflects that the W3C believes this specification has been widely reviewed and satisfies the Working Group’s technical requirements. Resource Timing was published as CR just two months ago, along with High Resolution Time, which went from an Editor’s Draft to CR in just three months.
These APIs are a great example of how quickly new ideas can become interoperable standards that developers can depend on in modern HTML5-enabled browsers. Thanks to everyone in the W3C Web Performance Working Group for helping design these APIs and to other browser vendors for starting to implement these APIs with an eye towards interoperability.
—Jatinder Mann, Program Manager, IE Performance