Capybara testing... ignores javascript

I like to use code like
<a href="javascript:void(0)" id="login_activator">Login</a>
which, when clicked, would trigger a jQuery action defined in my
application.js file to toggle the display of a div somewhere (in this
case, a div that is a partial for a login form).

But click_link "Login" fails to recognize this kind of anchor tag!

Worse, would Capybara even catch the new div that was originally
hidden because it was like
<div style="display:none">
...
</div>

So I'm having lots of trouble defining a step definition in which all
I want to do is login. It would be like what's at the bottom of this
page: https://github.com/cucumber/cucumber/wiki/ruby-on-rails ... but
the issue with click_link has stopped me.

Thanks in advance...