Graded browser support for the new theme for drupal.org

For the as of yet unnamed new theme for drupal.org, we are proposing graded browser support.

Here is a proposal as to what that could mean and how we propose to support the different browers.

The idea and the concepts are based on Yahoo YUI's graded browser support, which you can read more about here: http://developer.yahoo.com/yui/articles/gbs/

What is grading?

Grading means that we will define what levels of degraded functionality and experience we are willing to accept for different versions of web browsers across different versions of mainstream operating systems.

We plan to offer the following levels of support:

A-grade

A-grade support means that any sort of degraded experience or functionality on any part of the Drupal site should be considered unacceptable and treated as a bug in the theme.

As a general guideline, the browsers that are considered for A-grade support are those that fulfill the following requirements:
are widely used (at least 0.5-1% of drupal.org visitors)
are within the latest two or three major releases of that particular browser that are no more than four years old
are on the latest bugfix (patch) release to that major release series
are not more than four years old

B-grade

B-grade support means that slightly degraded experience or functionality is considered acceptable is considered as long as all of the main features of the site remain usable and accessible.

For example, the loss of rounded corners on elements is acceptable, as long as they degrade gracefully to square shapes. Likewise, the loss of drop-down navigation is considered acceptable, as long as no content is rendered inaccessible by that loss of functionality.

Also, some cutting edge features of the new drupal.org will be exempted from this rule, in particular the personalised dashboard, but wherever functionality is impaired, the page should still not appear to be broken, and a clear warning messge should appear notifying the user that whatever he's trying to do will not work with his choice of web browser.
Other issues, like layout bugs, unusable functionality and visual should be treated and fixed like bugs.

B-grade support will as a general guideline be offered to browsers that are widely used (at least 0.5-1% of drupal.org visitors), but do not fulfill the rest of the requirements for A-grade support.

C-grade (unsupported)

C-grade support means that this browser is basically unsupported. If trivial changes can be made to better support these browsers, they will be handled as feature requests, and if patches are made they will be merged if they do not disrupt the higher grades of support and the patches do not introduce unnecessary extra complexity to the theme. C-grade support is offered to all browsers not covered by the other grades, unless explicitly excluded from this rule.

Example chart

Here is a non-exhaustive example of based on the above rules applied, on the time of this writing (2009-01-18).

Existing stats

drupal.org stats (Google analytics)
drupal.org stats (awstats)

drupal.org, collected with awstats, Jan 2009

1. Firefox 3
   55.2%
2. IE 7
   17.1%
3. Safari
   7.9%
4. IE 6
   4.7%
5. Firefox 2
   3.8%
6. Opera
   2.8%
7. Mozilla
   2.3%

api.drupal.org, collected with Google Analytics, # visits, 22/Jan/2009

1. Firefox
   112,384 76.20%
2. Internet Explorer
   11,105 7.53%
3. Safari
   7,871 5.34%
4. Chrome
   6,594 4.47%
5. Opera
   5,883 3.99%
6. Mozilla
   2,135 1.45%
7. Mozilla Compatible Agent
   533 0.36%
8. Camino
   365 0.25%
9. Konqueror
   326 0.22%
10. SeaMonkey
    192 0.13%

Association.drupal.org, collected with Google Analytics, # visits, 22/Jan/2009

1. Firefox
   4,060 46.56%
2. Internet Explorer
   3,523 40.41%
3. Safari
   585 6.71%
4. Chrome
   240 2.75%
5. Opera
   153 1.75%
6. Mozilla
   57 0.65%
7. Playstation 3
   37 0.42%
8. Konqueror
   24 0.28%
9. Mozilla Compatible Agent
   13 0.15%
10. Camino
    8 0.09%