问题
It was working fine before, now whenever I run the script it just opens Firefox then does nothing. It works when running with chromedriver though.
Tried updating gems etc, but no success.
回答1:
The latest Firefox version will no longer work with the legacy Firefox Driver. To use Watir with Firefox 48+ you need to download geckodriver and follow the instructions for Ruby.
Since Geckodriver is not yet feature complete, you most likely will want to continue using the legacy Firefox Driver, which means either using Firefox ESR or downgrading to Firefox 47.0.1.
来源：https://stackoverflow.com/questions/39185507/watir-webdriver-doesnt-do-anything-after-opening-browser-firefox