This is using selenium with capybara for test automation and these help greatly if the devs did not supply names or ids on the frames.

This method is used to interact with elements inside the the specified frame located by some dom property

def within_open_frame(dom_property,dom_value)
    page.driver.browser.switch_to.frame(get_frame_index_by_dom_property(dom_property,dom_value))
    yield
    page.driver.browser.switch_to.default_content
end

This method returns the specified frames index by any dom property.

def get_frame_index_by_dom_property(dom_property,dom_value)
    frame_array = page.all('iframe')
    obj = frame_array.select { |frame| frame[dom_property.to_sym] =~ /#{Regexp.escape(dom_value)}/}.first
    frame_array.index(obj)
end