Tutorial: Comment Feature

Comment Feature

The comment feature is an Enketo extension to the OpenRosa XForm spec that allows form designers to add a comment widget to individual questions. If funding allows this could quite easily be extended further by adding a comment to a group or the form as a whole.

This feature has the following characteristics:

  • A comment is coded in XForms like a separate question. It has it's own XML data node. This means that XPath can be used to add form logic that references this question, e.g. a dynamic "required" expression that specifies that a particular question is required unless it has a comment.
  • The for attribute, in the http://enketo.org/xforms namespace, is used on the <bind> element to link a comment to a question.
  • An appearance is used to instantiate the widget. Without this appearance the comment input would show up as a regular question (and the for attribute would be ignored).
  • Optionally a custom-namespaced attribute could be added to the data node in the model in the XForm definition. Enketo will not use that information but it could be helpful to link user-entered data with a comment in the analysis.

This feature is not meant to be hand-coded into an XLSForm or XForm, as it quite tedious (but it can be done). It is meant to be added to advanced XLSForm or XForm form builders.

How to use

To add a comment widget to a question, the following needs to be defined in the XLSForm:


In XLSForm on the settings sheet, add a column namespaces and populate this with enk=http://enketo.org/xforms.

form_title namespaces
My Form enk="http://enketo.org/xforms"


Add a question of type text, optionally with appearance multiline, preferably immediately after the question node it refers to (only for future printability of records - it doesn't affect functionality). The name of the question is free to choose.

type name label appearance
text a Enter text
text a_comment Enter a comment multiline


Give this question the appearance comment to ensure the question will be displayed as a comment widget.

type name label appearance
text a Enter text
text a_comment Enter a comment multiline comment

Add a bind::enk:for column

For each comment question, add a reference to the question node it refers to in the bind::enk:for column, e.g. ${a}. The prefix enk corresponds with the namespace prefix added on the settings sheet.

type name label appearance bind::enk:for
text a Enter text
text a_comment Enter a comment multiline comment ${a}

Dynamic required

Optionally, if you'd like to make question "a" required only if there is no comment, you could use the regular XLSForm/XPath syntax. Nothing new here. You could do the same for relevant and constraint logic too.

type name label appearance bind::enk:for required
text a Enter text $a_comment = ''
text a_comment Enter a comment multiline comment ${a}

XForm sample

<?xml version="1.0"?>
<h:html xmlns="http://www.w3.org/2002/xforms" xmlns:enk="http://enketo.org/xforms" xmlns:ev="http://www.w3.org/2001/xml-events" xmlns:h="http://www.w3.org/1999/xhtml" xmlns:jr="http://openrosa.org/javarosa" xmlns:orx="http://openrosa.org/xforms" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
    <h:title>My Form</h:title>
        <myform id="myform">
      <bind nodeset="/myform/a" required="/myform/a_comment = ''" type="string"/>
      <bind nodeset="/myform/a_comment" enk:for="/myform/a"  type="string"/>
      <bind nodeset="/myform/meta/instanceID" jr:preload="uid" type="string"/>
    <input appearance="minimal" ref="/myform/a">
      <label>Enter text</label>
      <hint>required unless comment provided</hint>
    <input appearance="comment multiline" ref="/myform/a_comment">
      <label>Enter a comment</label>