Deprecations and Removals in Chrome 58

In nearly every version of Chrome, we see a significant number of updates and improvements to the product, its performance, and also capabilities of the Web Platform. This article describes the deprecations and removals in Chrome 58, which is in beta as of March 16. This list is subject to change at any time.

Remove case-insensitive matching for usemap attribute

The usemap attribute was formerly defined as caseless. Unfortunately implementing this was complicated enough that no browsers implemented it correctly. Research suggested that such a complicated algorithm is unnecessary, and even ASCII case-insensitive matching is unnecessary.

Consequently, the specification was updated so that case-sensitive matching is applied. The old behavior was deprecated in Chrome 57, and is now removed.

Intent to Remove | Chromestatus Tracker | Chromium Bug

Remove legacy caller for HTMLEmbedElement and HTMLObjectElement

That an interface has a legacy caller means that an instance can be called as a function. Currently, HTMLEmbedElement and HTMLObjectElement support this functionality. In Chrome 57 this ability was deprecated. Starting with Chrome 58, calling will throw and exception.

This change brings Chrome in line with recent spec changes. The legacy behavior is not supported in Edge or Safari, and it is being removed from Firefox.

Intent to Remove | Chromestatus Tracker | Chromium Bug

Mouse on Android stops firing TouchEvents

Until Chrome 57, Android low-level mouse events in Chrome primarily followed an event path designed for touch interactions. For example, mouse drag motion while a mouse button is pressed generates MotionEvents delivered through View.onTouchEvent.

But since touch events cannot support hover, hovering mousemoves followed a separate path. The design had many side-effects including mouse interactions firing TouchEvents, all mouse buttons appearing as left mouse buttons, and MouseEvents being suppressed by TouchEvents.

Starting with Chrome 58, a mouse on Android M or later will:

  • No longer fire TouchEvents.
  • Fire a consistent sequence of MouseEvents with appropriate buttons and other properties.

Intent to Remove | Chromestatus Tracker | Chromium Bug

Remove support for commonName matching in certificates

RFC 2818 describes two methods to match a domain name against a certificate: using the available names within the subjectAlternativeName extension, or, in the absence of a SAN extension, falling back to the commonName. The fallback to the commonName was deprecated in RFC 2818 (published in 2000), but support remains in a number of TLS clients, often incorrectly.

The use of the subjectAlternativeName fields leaves it unambiguous whether a certificate is expressing a binding to an IP address or a domain name, and is fully defined in terms of its interaction with Name Constraints. However, the commonName is ambiguous, and because of this, support for it has been a source of security bugs in Chrome, the libraries it uses, and within the TLS ecosystem at large.

The compatibility risk for removing commonName is low. RFC 2818 has deprecated this for nearly two decades, and the baseline requirements (which all publicly trusted certificate authorities must abide by) has required the presence of a subjectAltName since 2012. Firefox already requires the subjectAltName for any newly issued publicly trusted certificates since Firefox 48.

Intent to Remove | Chromestatus Tracker | Chromium Bug

The interface elements regions, addRegion() and removeRegion(), have been removed from the WebVTT spec and is removed in Chrome 58 to comply with the latest spec. We expect little impact from this removal since the feature was never enabled by default (meaning it was behind a flag). Those needing an alternative can use the VTTCue.region property which is being added in Chrome 58.

Chromestatus Tracker | Chromium Bug

WebAudio: remove AudioSourceNode interface

The AudioSourceNode interface is not part of the Web Audio specification, is not constructible, and has no attributes so it basically has no developer- accessible functionality. Therefore it is being removed.

Intent to Remove | Chromestatus Tracker | Chromium Bug

Remove webkitdropzone global attribute

The dropzone global attribute was introduced by the HTML5 drag and drop specification as a declarative method for specifying an HTML element's willingness to be the target of a drag-and-drop operation, the content types that can be dropped onto the element, and the drag-and-drop operation (copy/move/link).

The attribute failed to gain traction among browser vendors. Blink and WebKit only implement a prefixed form of the attribute, webkitdropzone. Because the dropzone attribute was removed from the spec in early March 2017 the prefixed version is being removed from Chrome.

Intent to Remove | Chromestatus Tracker | Chromium Bug

Deprecation policy

To keep the platform healthy, we sometimes remove APIs from the Web Platform which have run their course. There can be many reasons why we would remove an API, such as:

  • They are superseded by newer APIs.
  • They are updated to reflect changes to specifications to bring alignment and consistency with other browsers.
  • They are early experiments that never came to fruition in other browsers and thus can increase the burden of support for web developers.

Some of these changes will have an effect on a very small number of sites. To mitigate issues ahead of time, we try to give developers advanced notice so they can make the required changes to keep their sites running.

Chrome currently has a process for deprecations and removals of API's, essentially:

  • Announce on the blink-dev mailing list.
  • Set warnings and give time scales in the Chrome DevTools Console when usage is detected on the page.
  • Wait, monitor, and then remove the feature as usage drops.

You can find a list of all deprecated features on using the deprecated filter and removed features by applying the removed filter. We will also try to summarize some of the changes, reasoning, and migration paths in these posts.