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Saturday, April 13, 2013

Determining which version of Selenium goes with which browsers

Sometimes it is hard to know which version of Selenium you should be using. There is no hard and fast rule of which Selenium works with which browser but I have always found that you want a Selenium which was released after the browser but as close to the browser release date as possible.

It has been my experience that the latest version of Selenium and the latest version of Chrome go together. I have never found that the latest version of Selenium does not work with the latest version of Chrome.

On the other hand, I have seen Mozilla release a new version of Firefox and it takes a few weeks for a new version of Selenium to appear. During this period I find the latest version of Selenium does not work with the latest version of Firefox.

For example, Firefox 18.0 was released on 08-Jan-2013. At the time the latest version of Selenium was 2.28.0, released on 11-Dec-2012. If you updated to Firefox 18.0 the moment it was available, you might find that some of your Selenium tests started failing unexpectedly. Selenium 2.29.0 was released on 17-Jan-2013. I always disabled the ability for Firefox to automatically upgrade. When Selenium 2.29.0 was released, I upgraded my Selenium to 2.29.0 and my Firefox to 18.0.

You can see the release dates of Firefox (and other Mozilla browsers) on What I do is create a list of Selenium release dates from the Selenium download area ( I would then look at the Mozilla wiki and determine which Firefox had been released on an older date. From my example above:

11-Dec-2012    Selenium 2.28.0
30-Nov-2012    Firefox 17.0.1
17-Jan-2013    Selenium 2.29.0
08-Jan-2013    Firefox 18.0

Or in other words, if the project I am on has set a specific version of Firefox to support then I look for the Selenium which was released AFTER the Firefox release date. That is the combination I would test with.

For Internet Explorer I can find the release dates by searching for "Internet Explorer Release Dates". This currently takes me to IE Downloads. I also find the Wikipedia has an Internet Explorer page which gives release dates as well.

For the most part however, I let the version of Firefox drive which version of Selenium I need. Because I tend to have clients request IE7, IE8 and IE9 support, I find it best to go with the latest version of Selenium to support the latest version of IE.

Selenium does have limited support for Safari but this is typically not an issue. Much like IE, I let the version of Firefox drive which version of Selenium I need regardless of which version of Safari I need to support.

It should be noted that this is a general idea of how I determine which version of Selenium I want. If I use this rule and start finding that the version of Chrome matters, I would start trying to match the release date of Chrome to the release date of Selenium.