title: find_field with Poltergeist/Capybara
body: <p>I have a problem with Poltergeist. I can’t get the driver to locate a field on a page. What I want to do is to execute some js to make sure that the input field is empty before I start adding new text. I have a field with a label os "Skill list" and id of "user_skill_list". In order to make the step more generic I want to find the field by the label name and then get the id.</p>
  
  <pre><code>And(/^I delete the content of "([^"]*)"$/) do |label|
    field_id = page.find_field(label).native.attributes['id'].value
    page.execute_script("$('#{field_id}').val('');")
  end 
  </code></pre>
  
  <p>Here's the error message:</p>
  
  <pre><code>@javascript
    Scenario: Update user by removing                            # features/godmin/skills.feature:36
      Given "Thomas" skills are "rspec, testing"                 # features/step_definitions/godmin_steps.rb:63
      And I click on "Edit" for "Thomas"                         # features/step_definitions/godmin_steps.rb:43
      And I delete the content of "Skill list"                   # features/step_definitions/godmin_steps.rb:69
        Unable to find field "Skill list" (Capybara::ElementNotFound)
        ./features/step_definitions/godmin_steps.rb:70:in `/^I delete the content of "([^"]*)"$/'
        features/godmin/skills.feature:39:in `And I delete the content of "Skill list"'
  </code></pre>
  
  <p>```</p>
  
  <p>My cucumber set up is pretty basic. </p>
  
  <pre><code># features/support/env.rb
  ...
  require 'capybara/poltergeist'
  
  Capybara.javascript_driver = :poltergeist
  Capybara.default_max_wait_time = 5
  ...
  </code></pre>
  
  <p>Thank you. Please let me know if I should clarify my question. </p>