protractor: test for focus of field

How can I test if an input field is infocus with protractor? I'm doing this:

it('should focus email field', function(){
    expect(element(by.model('login.email')).getAttribute('id')).toEqual(browser.driver.switchTo().activeElement().getAttribute('id'));
});

This seems to work with chrome, but this test fails with firefox. Any ideas?

This is the failure message:

[firefox #1]   2) Login page should focus email field
[firefox #1]    Message:
[firefox #1]      Expected 'login' to equal ''.
[firefox #1]    Stacktrace:
[firefox #1]      Error: Failed expectation
[firefox #1]     at [object Object].<anonymous> (/Users/JasonKu/Desktop/jku/test/e2e/login-spec.js:38:69)
[firefox #1]