title: Rails jquery include blank in selection
body: <p>When a user is creating a new workorder, they first choose the workgroup, then they can select the Assigned To person from a dropdown containing a list of employees in that workgroup.  Do do that, I'm using jquery to create the picklist of employees in that group.</p>
  
  <p>But, I don't know how to add a blank selection via the jquery.</p>
  
  <p>This is the view code:</p>
  
  <pre><code>            &lt;%= f.grouped_collection_select :employee_id, Workgroup.order(:id), :employees, :group_name, :id, :employee_full_name, :include_blank =&gt; true %&gt;
  </code></pre>
  
  <p>This is the jquery cofeescript:</p>
  
  <pre><code>employees = $('#workorder_employee_id').html()
  $('#workorder_workgroup_id').change -&gt;
    group = $('#workorder_workgroup_id :selected').text()
    options = $(employees).filter("optgroup[label='#{group}']").html()
    if options
      $('#workorder_employee_id').html(options)
      $('#workorder_employee_id').parent().show()
    else
      $('#workorder_employee_id').empty()
      $('#workorder_employee_id').parent().hide()
  </code></pre>
  
  <p>How can I add a blank in the picklist?</p>
  
  <p>Thanks!</p>