Sencha, maker of the Sencha Touch Framework for HTML5 and JavaScript based mobile applications, commented on some so-called myths concerning performance of web-based applications on mobile platforms. Sencha specifically addresses the following statements:
- JavaScript performance is the most important factor regarding web applications
- JavaScript performance improvements are only due to hardware upgrades
- Future hardware upgrades will not affect web application speed
- JavaScript garbage collection is a performance killer
- Mobile browsers reached an upper limit of optimization
To invalidate these statements, Sencha offers a variety of benchmark results collected of the past years. Those benchmarks were run on different versions of iOS and Android on a number of hardware generations.
Sencha never experienced JavaScript to be to most limiting factor during development of Sencha Touch. Even though mobile devices are considerably slower than desktop computers, JavaScript performance is not a core problem since mobile applications are usually not computation intensive.
On the other hand, benchmark results over the last years show that JavaScript performance is clearly improving. Measuring with SunSpider on the same hardware (iPhone 3GS) over a number of OS releases shows that changes in the browser software (iOS 3 to iOS 6) has lead to an enhancement of about factor four. This trend is not unique for the iOS platform, but can also be seen on Android devices. Measuring with the same software on different device generations also shows a clear gain of speed along with hardware upgrades.
Besides analyzing JavaScript benchmarks, Sencha also offers some insights into DOM, SVG and graphics performance, which is - according to Sencha - more important to mobile web application performance than JavaScript itself.
Measuring DOM traversal and manipulation shows the same trends as measuring JavaScript: There are substantial improvements due to software and to hardware upgrades. Hardware upgrades, especially GPU acceleration, are also the reason for performance gains in the field of graphics and SVG.
Since Windows RT is even outperforming desktop computers by using GPU acceleration, there should be similar potential on iOS and Android platforms as the browser makers continue to offload operations to the GPU.
Sencha also considers the dynamic nature of JavaScript and garbage collection overhead as a general problem. The Sencha Framework itself addresses this by introducing a conceptual layer above the browser where object creation and destruction is handled. According to Sencha, without such a layer, one might run into performance issues.
Given the fact that browsers of different OS platforms clearly outperform each other in some specific area like JavaScript, DOM or graphics there is no reason to believe that browser optimization has come to an end. Obviously, each browser still has the potential for considerable speed improvements which lead in turn to better mobile web application performance.