I am able to execute the following code to move the slider handle, but the events triggered in the browser are not taking place.
page.execute_script(%Q($(\
resynchronize has been removed from Capybara 2.0 so user853088's answer for Selenium would now look like this:
module CapybaraSeleniumExtension def drag_by(right_by, down_by) driver.browser.action.drag_and_drop_by(native, right_by, down_by).perform end end