title: How to focus a form input field when page loaded
body: <p>In my rails 3 application, I have a view haml file with a form like following:</p>
  
  <pre><code>= form_for(:car, :url =&gt; cars_path) do |f|
    %p
      = f.label :carname
    %p  
      = f.text_field :carname /focus here
    %p
      = f.label :carnr
    %p
      = f.text_field :carnr
    %p
      = f.submit
  </code></pre>
  
  <p>I would like the <strong>input field</strong> <code>= f.text_field :carname</code> is in <strong>focus</strong> when the page is loaded. </p>
  
  <p>How to do it? Is it necessary to use jquery? or is there any Rails way to do the focus?</p>