HTML output uses removed HTML5 attribute: @compact

[markgif]

Expected Behavior

HTML output should use standard HTML markup supported by major browsers. @compact is no longer supported by Chrome, Firefox, Safari, Edge, Opera.

Actual Behavior

HTML output for html5 and xhtml uses @compact attribute, which was removed from HTML5. It was deprecated in HTML 4 about 20 years ago.

HTML5 spec, section 16.2 Non-conforming features:
https://html.spec.whatwg.org/#non-conforming-features
Paraphrase of the spec:

The following attributes are obsolete (though the elements are still part of the language), and must not be used by authors:
compact on dl elements
compact on menu elements
compact on ol elements
compact on ul elements

Possible Solution

Add a compact value in @class, and make the CSS match that?

Steps to Reproduce

1. In DITA 1.3 XML topic, add @compact to the root element of a list like <ul>:

   <ul compact="yes">
       <li>text</li>

2. Run the html5 or xhtml transtype on it.
3. The HTML output uses @compact.
   html5:

   <ul class="ul" compact>

   xhtml:

   <ul class="ul" compact="compact">

   CSS:

   *[compact=yes] > li {
   margin-top: 0; }
   *[compact=no] > li {
   margin-top: 0.53em; }

The Oxygen XML editor gives an error if you open the HTML file:

The “compact” attribute on the “ul” element is obsolete. Use CSS instead.

Environment

• DITA-OT version: 4.1.1
• Operating system and version:
  Windows 10
• How did you run DITA-OT?
  Oxygen GUI
• Transformation type:
  html5, xhtml

[jelovirt]

The @compact is one of those features of DITA that I think is very rarely used. We should replace this with outputting class="compact" in HTML5 and XHTML.

[markgif]

@compact in DITA XML is still used quite a bit, according to the OASIS DITA TC. @fwegmann asked them. The TC plans to keep @compact in DITA 2.0. But it's long gone in HTML. We've been discussing compact lists in the Lightweight DITA Subcommittee and I discovered this.

[chrispy-snps]

Testcase that applies @compact="yes" to <ul>, <ol>, <sl>, and <dl>: 4298.zip

[markgif]

I have a request on this. Recently in the Lightweight DITA Subcommittee we decided to add the attribute @data-compact to the HTML5 flavor of Lightweight DITA (aka HDITA), instead of adding a fixed @class value of "compact". Can we get you to use @data-compact="yes" or @data-compact="no" instead of the @class syntax above?

Example:

HTML5 and HTML5 XML syntax ("XHTML")
<ul class="ul" data-compact="yes">

CSS

*[data-compact=yes] > li {
margin-top: 0; }
*[data-compact=no] > li {
margin-top: 0.53em; }

[chrispy-snps]

@jelovirt, @robander - this represents a departure from precedent for capturing element characteristics in the HTML. I think we should discuss it in the next monthly call.

[markgif]

I would not mind attending this meeting, can I?