Developers are responsible for testing their websites and applications against the three most recent versions of commonly used browsers, listed below. Developers should test these browsers on multiple platforms.

Commonly Used Web Browsers

The data for the most commonly used Web browsers by visitors to are:

Browser Dec 2011 - Feb 2012 Mar-May 2012 Jun-Aug 2012 Sep-Nov 2012 Dec 2012 - Feb 2013 Mar-May 2013
Safari 26.2% 24.2% 26.0% 28.2% 29.1% 29.6%
Google Chrome 20.1% 23.3% 22.2% 24.8% 26.1% 26.1%
Internet Explorer 25.7% 25.2% 24.7% 22.1% 20.4% 20.5%
Firefox 24.5% 23.6% 23.2% 21.6% 20.2% 19.2%

Developers may test against less commonly used browsers but are not required to do so.

Web Visitors Browser Recommendations

Please refer to the Web Browsers page, which is geared toward Web visitors. The page contains browser recommendations including information about JavaScript, cookies and SSL encryption, and a list of popular plug-ins to download.

Develop for Your Community

In addition to testing against the most commonly used browsers and platforms, developers are also responsible for testing their sites and applications according to their target audience. If developers are creating or maintaining content or applications that have a specific target audience, e.g., K-12 teachers, they should determine what their browser usage is for that audience and make testing decisions based on that data.  Access to website analytics tools such as Urchin is available by contacting the Web Technologies Team.

In rare circumstances, some campus applications may not support all of the commonly used browsers due to special application needs or possible bugs in the browsers. Developers should clearly inform users if that is the case with their application.

Developers are discouraged from implementing any browser-specific features that do not break gracefully in all commonly used browsers.

Up-to-date Browsers

In addition to testing against popular browsers, developers should ensure their own browsers are up-to-date and secure by regularly downloading and installing patches and updates.