1212289 - Display presentational hints in the inspector's rule-view

Status: NEW

(DevTools :: Inspector, enhancement, P3)

Description

[Patrick Brosset <:pbro>]

This came up today on IRC.

Image a page that has, somewhere, this markup: <iframe width="200">
Using the inspector, it might not be immediately visible to the user where the 200px width comes from.
I think the reflex would be to look at the rule-view, but only CSS is shown there obviously, so this width wouldn't be there.
Then you might think of looking in the box-model tab which would tell you that, indeed, the iframe is 200px wide, but won't tell you where this size comes from in the code.
Eventually, you would find the width attribute in the markup-view.

After discussing this some more with Ms2ger on IRC, I learned that presentational HTML attributes like this were translated into CSS properties and treated as if part of a 0-specificity rule inserted at the beginning of the author's style sheet.

See this:
http://www.w3.org/TR/2011/REC-CSS2-20110607/cascade.html#preshint
and this:
https://html.spec.whatwg.org/multipage/rendering.html#presentational-hints

So, maybe it would make sense to display them in a CSS rule in the rule-view after all, maybe in a section titled "HTML presentational attributes" and displayed at the very bottom of the rule-view.

Comment 1

[kud]

Thanks @pbro :)

Comment 2

[Patrick Brosset <:pbro>]

Bug triage (filter on CLIMBING SHOES).