Semantic HTML for confirmation, error and warnings

问题:

What are people's opinions on semantic HTML for confirmation, error and warnings messages?

Currently I have something simple like:

<div class="message message-warning">
     <h3>Message Title</h3>
     <p>Message text</p>
</div>

Whereby the message-warning class gets replaced by message-confirmation or message-error if the message is a different type.

Is there a more semantic way of marking this up?

回答1:

May I suggest <figure>?

Excerpt from HTML5 Doctor (and they, from W3C):

The figure element represents a unit of content, optionally with a caption, that is self-contained, that is typically referenced as a single unit from the main flow of the document, and that can be moved away from the main flow of the document without affecting the document’s meaning.

Lets answer the questions first:

• Is such a dialog a single unit? Yes
• Is such a dialog self-contained? Yes
• Can such a dialog be moved away from the document without affect the document meaning? Yes

Yes, it fits a <figure> perfectly.

And, the <figcaption> is especially good for title bars / headings.

So, I'd go with <figure> without even trying to look further:

<figure id="dialog-box" class="warning">
    <figcaption>Message Title</figcaption>
    <p>Message text</p>
</figure>

回答2:

NEW ANSWER: Use the <dialog> element, and call .show() instead of .showModal(), or give it the open attribute if rendering server-side.

As long as it’s not shown modally, it won’t block interactions with other page content.

---

Old answer (before <dialog> was a thing):

Alerts are one of the semantics that ARIA added to HTML, because there's no straightforward way of doing in "pure" HTML. Hence:

<aside role="alert">
  <h2>Message Title<h2>
  <p>Message Text</p>
</aside>

I personally like to use <aside> as the element to slap the role on — it's technically not part of the page content, as described by Jeff Lindblom's answer.

Having a "semantic" CSS selector for this is easy enough:

[role="alert"] {
  font-size: 2em; /* or what have you */
}

回答3:

The <figure> idea is interesting, but I don't think it fits here. What it's missing is the actual content to justify use of the tag. According to the spec, <figure> represents a "unit of content" - meaning an image, diagram, code block, etc. that may optionally have a caption for this content (<figcaption>). It would be a stretch to say that the message outside the <figcaption> represents an appropriate unit of content.

We should also be cautious of using <h#> tags in this instance, as the message is secondary content, and should probably not be part of the document outline.

One could argue, under the revised spec, that an <aside> would be appropriate. It's now considered "tangential content" when used outside an <article>.

<strong> would be appropriate for the "title" of the message, since it's a semantically more important part of the message, but not a document header. So the code might look so:

<aside class="warning-or-whatever">
    <strong>Message Title</strong>
    <p>Message Text</p>
</aside>

One could also argue, since there's nothing specifically created for such a feature, that a good old-fashioned, semantically meaningless <div> might be the best element. I guess it comes down to how "tangential" you feel your messages are.

Thanks, Jeff

回答4:

No. There is no element in HTML that denotes a confirmation, error, or warning message.

Technically, the samp element has been defined as “sample output from programs, scripts, etc.” in HTML 4.01 and in HTML 3.2, though originally in HTML 2.0 as “sequence of literal characters, typically rendered in a mono-spaced font” and being somewhat redefined in HTML5 as “(sample) output from a program or computing system”. So its meaning is rather vague, and it’s not used much, so there is no real point in using it. But it might be argued that it is acceptable to use samp markup for any message from a program. It is a text-level element, so you would need to use it separately inside h3 and inside (any) p, more or less breaking the structure.

It might also be said that the messages are quotations from an external source, so they could be wrapped inside blockquote.

The use of h3 vs. some other markup isn’t really a semantic question, but structural: is this a heading for some content at the 3rd level of nesting?

回答5:

I think the strong element is an appropriate element for such messages.

You could use several strong elements to indicate the importance of the message:

<strong>Login successfully.</strong> <!-- confirmation --> 
<strong><strong>Wrong login data.</strong></strong> <!-- warning/error -->

If it’s stand-alone message for which a heading is warranted, use a section element instead of a div. In case of serious errors that apply to the whole page, it should be the first element on the page.

Various variants are possible:

<section class="message message-error">
  <h1><strong><strong>Error:</strong> Wrong login data.</strong></h1>
  <p>The username and/or password is wrong. Try …</p>
</section>

<section class="message message-error">
  <h1>Error</h1>
  <p><strong><strong>Wrong login data.</strong></strong></p>
  <p>The username and/or password is wrong. Try …</p>
</section>

<section class="message message-error">
  <strong><strong>Wrong login data.</strong></strong>
</section>

<section class="message message-error">
  <p><strong><strong>Wrong login data.</strong></strong> Try …</p>
</section>

Which one to use depends on the kind of message, if the exact error is know, if additional help text is provided, and if several message could come up at the same time.

Note that you probably don't want to use a heading for messages that apply to a single input element (e.g. when the user didn't fill out a required field or entered wrong content etc.), as these error messages should be in the corresponding label or directly next to the input element.

For accessibility, you should have a look at WAI-ARIA. Maybe aria-live="assertive" might be an appropriate way to mark error messages.

回答6:

If you want to go semantic, you can use a semantic-web approach by making an ontology for messages and warnings and use RDFa to embed it in your HTML.