styfle/breaking-changes-web

💢 A list of breaking changes to the web platform

Breaking Changes to the Web Platform

Over the years there have been necessary changes to the web platform that caused legacy websites to break.

Below is a list of those changes.

• SSL removed in favor of TLS wiki (June 2015)
• Adobe Flash (SWF) End of Life wiki (December 2020)
• <applet>, <blink>, and many other tags removed html5 (January 2008)
• window.showModalDialog removed operablog (August 2014)
• Passive touch listeners by default googleblog (January 2017)
• Forms with passwords marked Not Secure over HTTP googleblog (January 2017)
• Array.prototype.flatten breaks MooTools bugzilla renamed to Array.prototype.flat (May 2018)
• Full page layout is no longer synchronous googleblog (May 2018)
• HTML Imports (part of Web Components v0) deprecated googleblog (October 2018)
• WebSQL is removed developer.apple.com (September 2019)
• Cookies changed from SameSite=None to SameSite=Lax by default chromestatus tweet (August 2020)
• alert() and confirm() removed from cross-origin iframes chromestatus tweet (July 2021)
• Removing HTTP/2 Server Push from Chrome chromeblog (August 2022)

breaking-changes-web's Issues

unload event

https://groups.google.com/a/chromium.org/g/blink-dev/c/dvusqw9-IhI

A Permission-Policy for creating unload event listeners will be added.

Initially, the default policy will be set to allow. From there, Chrome will gradually migrate the default policy to deny (i.e. increasingly disallow the creation of unload event listeners, eventually reaching a state where deny fully becomes the default policy). The ultimate goal is to remove support for unload event.

Intent to Remove: HTTP/2 and gQUIC server push

https://groups.google.com/a/chromium.org/g/blink-dev/c/K3rYLvmQUBY/m/vOWBKZGoAQAJ

https://news.ycombinator.com/item?id=25064855

Many others deprecations

See https://developers.google.com/web/updates/capabilities for a full list

For example, see https://developers.google.com/web/updates/2018/11/web-audio-autoplay

document.domain

https://developer.chrome.com/blog/immutable-document-domain/

Dating

For whom the events were added by, could they also include the times, too?

marquee is unlikely to be removed

The marquee element is still in the spec and unlikely to be ever un-shipped. One reason is specifically legacy websites. A lot of websites of India are still using it and for webcompat reasons, we can't just break these sites.

Add a few more: applet and keygen

Two recent removals from the platform include the applet and keygen elements. An in-progress removal, which may or may not be successful, is the AppCache feature.

https://whatwg.org/faq#removing-bad-ideas

Also ShowModalDialog is another breaking change.