Adobe’s once-ubiquitous Flash Player, a browser-based runtime for displaying rich media content on the Internet, has reached the end of the road, with the company having made the final scheduled release of the technology for all regions outside mainland China.

The final release was made on December 8. Adobe will no longer support Flash Player after this month; Flash content will be blocked from running in Flash Player beginning on January 12, 2021.

Adobe advises all users to immediately uninstall Flash Player to protect their systems. In release notes, Adobe thanked customers and developers who have used the technology and created content leveraging it during the last two decades. An end-of-life general information page has been posted.

Adobe announced in July 2017 that it would discontinue Flash Player at the end of this year. Flash technology succumbed to perceptions of it as proprietary technology in an era when standards-based technologies such as HTML5 began to gather momentum. Adobe cited WebGL and WebAssembly as now-viable alternatives.

Flash sustained a critical blow when Apple declined not to support it on the iPhone and iPad mobile devices. Additionally, security issues plagued Flash, and major browser vendors began moving away from the technology. Video content site YouTube backed away from Flash in 2015, opting for HTML5.

By giving three years’ advance notice, Adobe hoped to provide enough time for developers, designers, businesses, and others to migrate their Flash content to new standards. The timing of the Flash end-of-life was coordinated with major browser vendors.

Firefox users can expect improved JavaScript performance in the Firefox 83 browser, with the Warp update to the SpiderMonkey JavaScript engine enabled by default.

Also called WarpBuilder, Warp improves responsiveness and memory usage and speeds up page loads by making changes to JiT (just-in-time) compilers. Optimizing JiT is changed to rely solely on the CacheIR simple linear bytecode format, specifically, CacheIR data collected by the baseline tiers. The new architecture leveraged in the browser also is described as being more maintainable and unlocking additional SpiderMonkey improvements.

Firefox 83 was published in beta October 20 and is scheduled to be released November 17. Warp has been shown to be faster than Ion, SpiderMonkey’s previous optimizing JiT, including a 20 percent improvement on Google Docs load time. Other JavaScript-intensive websites such as Netflix and Reddit also have shown improvement.

Basing Warp on CacheIR enabled removal of code throughout the engine that was needed to track global type inference data used by IonBuilder, resulting in speedups. Although IonBuilder and WarpBuilder both produce Ion MIR, an intermediate representation used by the optimizing JiT back end, IonBuilder had a lot of complex code not needed in WarpBuilder. Warp also can do more work off-thread and needs fewer recompilations. Plans call for continued optimizations on Warp, which at present is slower than Ion on some synthetic benchmarks.

Warp has replaced the front end — the MIR building phase — of the IonMonkey JiT. Plans call for removing the old code and architecture, which is likely to happen in Firefox 85. Additional performance and memory usage improvements are anticipated as a result. Mozilla also will continue to incrementally optimize the back end of the IonMonkey JiT, as Mozilla believes there is still room for improvement for JavaScript-intensive workloads. Also in development is a tool for web developers and Mozilla to explore CacheIR data for a JavaScript function.

Microsoft and Google are partnering to promote web browser compatibility around a number of CSS (Cascading Style Sheets) features, with an effort called #Compat2021.

Also involving open source software consulting firm Igalia and the broader web community, #Compat2021 aims to improve compatibility in five specific areas:

• CSS Flexbox, a CSS module that defines a CSS box model optimized for user interface design and the layout of items in a single direction.
• CSS Grid, for dividing a page into regions or defining the relationship in terms of layer, position, and size, between parts of a control built from HTML primitives.
• CSS Position: sticky, or sticky positioning, which is akin to a hybrid of relative and fixed positioning.
• CSS aspect-ratio property, pertaining to a CSS property setting a preferred aspect ratio for the box, to be used in the calculation of auto sizes and other layout functions.
• CSS transforms, for rotating, scaling, skewing, or translating an element.

The joint working group involved in the project identified these focus areas based on the number of related bugs in each vendor’s tracking system, feature usage data, survey feedback, CanIUse data, and web-platform-tests test results.

While working group members will focus on their respective implementations, the Microsoft Edge team plans to contribute fixes to the Google-sponsored Chromium project to pass all CSS Grid tests in 2021 and to support improving interop across browsers.

#Compat21 was announced on March 22. Progress on the project can be tracked on the Compat 2021 dashboard.