Caption shortcode `class` attribute stripped by TinyMCE

[dominicp]

A class attributed is listed as supported in the ​Codex and it looks like support was added in [27404]. But, if I add one manually in text view, and switch back to the visual editor, the attribute is stripped.

Unfortunately, I'm not familiar enough with the WP internal javascript to pinpoint exactly where this is happening.

[SergeyBiryukov]

Confirmed.

[knutsp]

Keep the caption shortcode class attribute in TinyMCE

[knutsp]

This is my first patch touching Javascript. Not sure this approach is acceptable, but worth a try.

[DrewAPicture]

This looks pretty good at a glance. If we're gonna introduce a new var here, can we at least use a complete word instead of another cryptic abbreviation? Any input @azaozz?

[kadamwhite]

Alter existing patch to use "align" instead of "aln", and make alignment class regex case-insensitive

[kadamwhite]

This patch looks good, but I've altered the name of the new variable to be align (for readability); made the regex for the alignment class case-insensitive; and standardized the whitespace around + operators within the lines touched by the path.

The reasoning for making the regex case-insensitive is that putting in mis-cased values into the 'align' attribute was causing an issue where the invalid attribute value and "wp-class" would get inserted into the user's shortcode class attribute value. Invalid alignment values (e.g. align="sideways") will still trigger this behavior, and that may be inevitable, but making the regex case-insensitive was a quick way to mitigate it without altering the functionality of the patch.

[azaozz]

In [29380]:

TinyMCE: add support for class attribute on the caption shortcode. Part props knutsp, kadamwhite, fixes #28951.