Invalid HTML around the input field for searching themes

[takayukister]

There seems to be an invalid HTML structure in the Themes (wp-admin/themes.php) and Add Themes (wp-admin/theme-install.php) pages in the admin screen. There is an input field for searching themes, but it's not in any ancestor <form> element.

I'm not sure, but it might cause troubles in some environments such as screen readers. So I propose adding <form> element somewhere appropriate to make it valid HTML.

I found this issue at WordCamp US Contributor Day (Accessibility Team).

@takayukister: Thanks for your ticket!

That makes sense, can someone from the a11y team weigh in on best practices here? Thanks.

Out of curiosity, how did you discover this issue: where you using a tool to scan pages for issues or looking for specific issues?

Technically, this is OK. Having input elements outside of form elements should pass W3C validation.

However, I understand the concern. Potentially, having the label, input, and submit elements outside of a containing form element, in essence, goes against the "Robust" principle of web accessibility. Specifically, the guideline pertaining to this issue is a Level A guideline. Emphasis is mine:

4.1.1 Parsing: In content implemented using markup languages, elements have complete start and end tags, elements are nested according to their specifications, elements do not contain duplicate attributes, and any IDs are unique, except where the specifications allow these features. (Level A)

The main concern is this: when HTML elements are not used in the recommended way, user agents may render them in unexpected ways. It can also become a problem for compatibility with older or even future browsers, devices, or other software.

Here are links to this guideline for 4.1.1: ​http://www.w3.org/TR/WCAG20/#robust and the W3C's recommendation for forms: ​http://www.w3.org/TR/html5/forms.html#forms

Since this doesn't exactly map to a true validation issue, it can be left as-is. However, I'd recommend enhancing these inputs to have a form wrapper for compatability when, say, JavaScript issues occur or a user has their JS disabled. That way, you can explicitly give an address for the input to submit to.

However, I'd recommend enhancing these inputs to have a form wrapper for compatability when, say, JavaScript issues occur or a user has their JS disabled. That way, you can explicitly give an address for the input to submit to.

It's probably important to note here that these search input fields are pretty much entirely reliant on JavaScript. They will automatically filter the list of themes based on what the keyword is, but will also not appear at all when JS is disabled. It also doesn't have a submit button, so it's not usable as a "traditional form" in its current state.

Regardless of what we do in regards to adding the form element and making it work without JS, I'd probably strongly urge to not keep it inside of the h1 on themes.php because of what it does to the heading list:

I'd like to address this in the next release cycle. See also related #31818.

Replying to Cheffheid:

Regardless of what we do in regards to adding the form element and making it work without JS, I'd probably strongly urge to not keep it inside of the h1 on themes.php because of what it does to the heading list

Related: #26601

added form for theme search filter

@aryamaaru Thanks for your patch. I'm updating the keywords accordingly. Note that there is no need to modify minified JavaScript files as these will be generated automatically.

Besides layout issues, the form will need to have its default action prevented otherwise pressing Enter will submit the form causing a page reload.

After the work done on #26602 the only thing left here would be wrapping the search field in a form element. Moving to 4.8.

Refreshed patch.

In 40572:

Accessibility: Wrap the installed themes search field within a form element.

Valid code is important not just to formally meet the specification, but also to
ensure user agents, including assistive technologies, can accurately interpret
and parse content. When HTML elements are not used in the recommended way,
user agents may render them in unexpected ways. It can also become a problem for
compatibility with older or even future browsers, devices, or other software.
See W3C WCAG 4.1.1.

Props takayukister, aryamaaru.
Fixes #34881.

Looks like this has caused the search input on Add Themes to be missing.

There is a search-form field there that also needs to be converted to wp-filter-search-form https://core.trac.wordpress.org/browser/trunk/src/wp-admin/theme-install.php?rev=40572#L167

Fixes the theme install page to show the search field with proper styling and alignment.

I'd take this as an opportunity to use a form element for the theme install page too, see 34881.3.diff​

In 40586:

Themes: Fix missing search field in the Theme Install screen after [40572].

Props desrosj, cristianozanca for reporting.
Fixes #34881.