Starting a webdriver server

If you aren't sure about what a webdriver server is, then download the Selenium standalone server.

It is a .jar file. Make sure you have Java and Firefox installed.

Assuming the file you downloaded is called selenium-server-standalone-2.45.0.jar, you can start the server with:

java -jar selenium-server-standalone-2.45.0.jar

If you are using OS X with Homebrew you can install the Selenium standalone server with:

brew install selenium-server-standalone

Follow the Homebrew post-install instructions to run the server locally.