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Re: Best practices showing revisions (strikethroughs, etc.)

for

From: Wyant, Jay (MNIT)
Date: Jan 9, 2014 8:09AM

To make sure I am clear:

- Both <del> or <s> are acceptable tags for strikethrough- the key is to alert the screenreader user to set to a proofreading scheme (in JAWS by pressing alt-insert-s). Otherwise the screen reader will simply ignore all text within those tags.

- However, the solution will not address iOS systems using Voiceover, which does not provide a proofreading mode. Users relying on Voiceover will not be able to distinguish the strikethrough text.

- Would an alternative, such as this strikethrough code I found on Karl Groves' site work for all environments?: <span style="text-decoration: line-through;">

Thoughts?

Jay

-----Original Message-----
From: Jukka K. Korpela [mailto: <EMAIL REMOVED> ]
Sent: Tuesday, January 07, 2014 5:07 PM
To: <EMAIL REMOVED>
Subject: Re: [WebAIM] Best practices showing revisions (strikethroughs, etc.)

2014-01-07 22:51, Wyant, Jay (MNIT) wrote:

> We are concerned that there
> doesn't seem to be a standard for showing document revisions in html
> format. As an example, here's a typical page on the Revisor's Bill
> site: [...]
> Deletions are identified by the tag <s></s>, additions by the
> underline tag.

Both according to HTML 4 and to HTML5 CR, deletion is to be marked with <del>, insertion with <ins>. In practice, their impact is simply that <del> causes overstriking, <ins> causes underlining. I don't think there is any browser, search engine, or other relevant program that cares about the "semantics" of these elements.

> (A March 27 note in the WebAIM archives expressed concerns that this
> tag is deprecated.

The <s> and <u> elements are deprecated in HTML 4. In HTML5 CR, the situation is in principle worse: they are conforming elements, but their definitions are obscure and subject to varying interpretations. It's really just a way of "saving" these presentational tags.

In practice, using <s> and <u> vs. <del> and <ins> does not really matter. I suppose they use <s> and <u>, since they have longer history in HTML: they are supported by all graphic browsers (though possibly not all character cell browsers).

> Another note argued against
> using the <del> tag.)

I don't know why, but I can argue against the use of overstriking for deletion and underlining for insertion, no matter how you achieve that.
Overstriking makes text more difficult to read. Underlining is easily confused with links; it also breaks descenders of letters, somewhat decreasing legibility.

> Is there any reference source for standards for such revision marks?

Regarding HTML, the "standards" we have tell you to use <del> and <ins>.

You can do so, of course. But I would then consider using style sheets to make things more accessible to people using common graphic browsers visually. For example,

/* remove overstriking on mouseover: */
del:hover { text-decoration: none }
/* replace underlining by dashed line under in different color: */ ins { text-decoration: none; border-bottom: dashed green 2px; }

For non-visual browsing, you would need something else.

Yucca