Update fallback content's behavior for ImageInputType and HTMLImageElement

DOM

Previously, there have been inconsistencies on the implementation of fallback content and its treatment as a replaced element for ImageInputType and HTMLImageElement. This led to interoperable issues between implementors. Examples: <input style="display: inline;" type=image alt="ALT"> <img title="foo"> <img src="foo" width=10 height=10 alt> Please see, https://github.com/yuzhe-han/images-fallback-content-1094763, for visual comparison.

Motivation

The behavior of ImageInputType's and HTMLImageElement's fallback content was not very interoperable, and not clearly specified. With this HTML spec PR (https://github.com/whatwg/html/pull/5315) the behavior has been more completely specified. Chrome will implement this modified behavior starting in M85. See https://github.com/whatwg/html/issues/5309, https://bugzilla.mozilla.org/show_bug.cgi?id=1196668, and tracking bugs for more details and conversation.

Documentation

Specification

Established standard

Status in Chromium

Blink components: Blink

Enabled by default (tracking bug) in:

Chrome for desktop release 85
Chrome for Android release 85
Android WebView release 85

Consensus & Standardization

After a feature ships in Chrome, the values listed here are not guaranteed to be up to date.

Firefox: Shipped/Shipping
Edge: No signal
Safari: Shipped/Shipping
Web Developers: No signals

Owner

yuzhehan@chromium.org

Intent to Prototype url

Intent to Prototype thread

Last updated on 2020-10-25