anchor.diff:    <% if doc.children.length > 0 %>
       <% if node_type(doc.node_type) == :element %>
         <span class="markup">&gt;</span></div>
  -      <% if error_id %>
  +      <% if error_id && errors && errors.count > 0%>
           <% popup_title, popup_button_text, popup_content = popup_attributes(errors) %>
           <% # button to display popup with error message(s) %>
           <% btn_errors = '' %>
  
positive.code:       <% attribute = att[1] %>
        <% if attribute.name != 'error_id' %>
          <% att_prefix = attribute.namespace.nil? ? "" : (attribute.namespace.prefix || "") %>
          <% att_name = att_prefix == "" ? attribute.name : "#{att_prefix}:#{attribute.name}" %>     
          <span class="attribute-name <%= error_attributes.index(attribute) ? 'attribute_error' : '' %>"> <%= att_name %></span>
          <span class="markup">=</span>
          <span class="attribute-value">"<%=attribute.value %>"</span>
        <% end %>
      <% end %>
   
    <% when :document %>
      <div>
        <span class="markup">&lt;?</span><span class="start-tag">xml</span>
  
negative.code: #   execution_errors
  
  %>
  <% return if doc.nil? %>
  
  <% error_id = (doc['error_id']) %>
  <div <%=  error_id ? %{id=xerror_#{error_id}} : '' %> class="indent ">
    <% if error_id %>
      <% # create error message to be displayed in popup %>
  