There are really two points gustav klimt here. It s not just about how to most efficiently execute J

A note from the editors: In each installment, an author from the W3C will keep you informed gustav klimt on what we're up to and how you can be a part of it. This column is from Jatinder Mann, Internet Explorer Program Manager and Editor in the W3C Web Performance Working Group. Jatinder would like to thank Working Group co-Chairs Arvind Jain and Jason Weber, and W3C's Philippe Le Hégaret for their input on the piece.
While a decade ago it may have been okay to go brew a pot of coffee while the computer was loading, today we all expect our software and devices to be fast and responsive. The same holds true for web performance. The load speed and responsiveness of a web application play a critical role in our choice of which applications gustav klimt we want to use. At the same time, how efficiently software runs plays a critical role in device battery life. No one wants to be carrying around a brick. Share This: Twitter Facebook Google+
To build fast web applications, web developers need to be able to qualitatively measure application performance, effectively use their hardware, and most importantly, gustav klimt know which patterns to optimize and which to avoid.
We found that web developers haven t had the right tools. Left on their own to guess, web developers in many cases only emphasized JavaScript performance and equated JavaScript performance with web performance.
However, web performance is truly a multi-dimensional problem. How quickly the network can download resources, how efficiently the CPU can perform web runtime operations, and the amount of available GPU memory all impact web performance. Let s take a closer look at an example I gave in a Build presentation involving five real world travel booking web applications: Kayak, Expedia, Priceline, gustav klimt Travelocity, and Orbitz. All of these sites have very similar gustav klimt elements gustav klimt on the page. They all have logos, banner ads, interactive real time flight data, etc. We would expect them all to have very similar performance characteristics.
Figure 1 shows the metrics for each of these sites, anonymized here to avoid poking at anyone. We can see that even though these travel sites have very similar functions, they have all been designed very differently. Some have more bytes coming down the wire, others have more JavaScript.   Total Size (k) Number of Elements CSS Rules Image Files Script Lines Site #1 3,697 1,504 1,392 41 77,768 gustav klimt Site #2 2,278 1,100 5,325 29 39,183 Site #3 1,061 2,673 1,105 66 12,643 Site #4 1,812 4,252 1,672 12 10,284 Site #5 1,372 900 3,902 6 38,269
Many developers would assume that the fastest site would be the one with the least number of formatted lines of JavaScript, like Site #4, or the one with the least bytes downloaded, like Site #3. However, that s not the case. Site #5 is actually the fastest, even though it has more JavaScript and bytes downloaded. Figure 2 breaks down the amount of time each of these sites spent in the different browser subsystems, subsystems all standards-based web browsers have.
There are really two points gustav klimt here. It s not just about how to most efficiently execute JavaScript, it s about how all of the browser gustav klimt subsystems can most effectively work together. Without the right tools, developers don t really know why their applications are slow and what to optimize.
Most web experts realized that there was a need for better interfaces to help developers measure their applications and write faster code. More importantly, there was a need for a forum to talk about performance problems that web developers faced and how to solve them.
At tech conferences, folks like Steve Souders and Arvind Jain from Google, Jason Weber from Microsoft, Jason Sobel from Facebook, and others started discussing performance-related issues, such as an accurate and interoperable way to measure page navigation gustav klimt time. These conversations soon led to the establishment of a working group in the W3C focused solely on performance. It was in the summer of 2010 that Jason Weber from Microsoft gustav klimt and Arvind Jain from Google were selected to co-chair the newly minted W3C Web Performance Working Group, chartered to identify and solve performance issues that developers encountered on the web.
Not everyone was certain all these competitors could work together. The first comment gustav klimt on the IE Blog post announcing this working group, referring to the Google and Microsoft co-chairing of the working group, was I bet the Richter scale could pick up the tension in that room. Fast forward to 2013 (and ignoring the fact that the Richter scale isn t an actual instrument), and the Web Performance Working Group can really be seen as an example of the ideal working group. In just three years, Microsoft, Google, Mozilla, Intel, DynaTrace, and others in this group have designed APIs to help developers measure their web applications more accurately and precisely than ever before ( Navigation Timing gustav klimt , Resource Timing , User Timing , Performance Timeline , High