Friday, July 1, 2011

A Comparison of Browsers: Popularity and JavaScript Compatibility

At the beginning of every month, new statistics are published on browser usage: At the onset of July 2011, as you can see from the diagram below, Chrome is closing in on Firefox, even as IE is losing its market share.

Source: StatCounter Global Stats - Browser Market Share

Popularity aside, it is also important to understand how their JavaScript implementations stack up. ECMA has made available a standardized test suite for the latest version of ECMA-262 edition 5.1, published 30 June 2011, known as Test262.

Once I learnt above the availability of these tests, it seemed like a good idea to test the browsers on my laptop. The tests were conducted on July 1, 2011. The results are given below for the browsers I tend to use [Browser Performance is tested against ECMA's Test262 Version, 30 June 2011, with 10934 tests]:



Time to Run (min.)



Fail to Load

Mozilla Firefox



10,662 262 0

Microsoft IE 9.0.8112.16421 20 10,634 300 0

Google Chrome

12.0.742.112 55

10,427 507 0


11.50 Build 1074 46

6,995 3873 66
Apple Safari

5.0.5 (7533.21.1) Crashes after ~2,500 tests in a little after 5 hours! ~2,500 20 ~8,414

The biggest surprise is that some of the browsers do not load all the tests; and, Apple Safari is the worst performer from this perspective, not being able to load more than 75% of the tests even after 5 hours of execution! And, Opera failed more than 35% of the tests!

Firefox, IE and Chrome have had the least hiccups, were able to load 100% of the tests, but failed 1.4%, 1.6% and 2.7% of the tests respectively.

All the tests were run on an ACER Aspire 4730Z, Pentium Dual-core CPU T4200 @ 2.00 GHz with 3GB RAM and Windows Vista Home Premium Service Pack 2, 32-bit. It takes about 50 minutes to run the tests on each browser.

The goal of my testing was primarily to assess JavaScript compatibility, and not execution speed.


  1. The Safari numbers made me curious. On my 4 year old machine, Safari ran the tests fine, and made it in about 25 minutes, although it failed around a thousand tests, and would therefore be placed after Google Chrome in your chart.
    Core 2 Duo, 2 Ghz, 4 GB RAM, Safari 5.0.5

  2. Is ECMA that standardization organization which approved OOXML in favor of MS even specification was incomplete at that time and it was impossible to implement based on that specification?
    It is shame that ISO approved it too (in scandal atmosphere). I know standards are business driven for many years now, but it is shame to see how credibility those standard organisation fells recent years due to money involved.

  3. @Jonathan: Maybe the culprit is the 3GB RAM in my laptop; in other words, if Safari works fine as long there is 3.5GB of RAM ... but, I contend, with only 3GB, Safari shouldn't crash.
    @Anonymous: I don't know about OOXML, but ECMAScript is the overseer of JavaScript specification.

  4. My first time here. Blue text on black?!?!???

    Atrocious usablility design and 20th century layout: I give this site a -5 in credibility.