Modern web guidance. A set of evergreen, expert-vetted skills for AI coding agents from the Chrome team, covering UI components, legacy code modernization, security, and performance. Install via npx modern-web-guidance@latest install, or as plugins for Claude Code, Copilot CLI, Vercel Agent Skills, and Antigravity. The skills can help with modern features like <dialog> modals, popover tooltips, container queries, passkeys, CSP, and improving Web Vitals. #tools #ai

https://developer.chrome.com/docs/modern-web-guidance

Firefox 151 release notes for developers. The release adds shadowrootslotassignment on <template> elements for declarative slot assignment, @​container style() queries, position-anchor: normal, the Document Picture-in-Picture API for always-on-top HTML windows, desktop Web Serial API, CanvasRenderingContext2D.lang, keyboardLock in requestFullscreen(), and the experimental field-sizing property for form controls. #firefox #browser

https://developer.mozilla.org/en-US/docs/Mozilla/Firefox/Releases/151

State of AI 2026 survey results. @sachagreif’s annual survey of 7,258 developers shows AI-assisted coding has gone mainstream, with respondents now generating 54% of their code with AI, up from 28% last year. Claude Code leads in positive sentiment among coding agents at 42.3%. Spending on AI tools keeps rising as the industry shifts from VC-subsidized pricing to sustainable monetization. Hallucinations remain the top pain point. #ai #survey

https://2026.stateofai.dev/en-US

Browsers treat big sites differently. @denodell reveals how Safari and Firefox quietly ship thousands of lines of site-specific patches to keep popular websites working. WebKit’s Quirks.cpp and Firefox’s about:compat both contain interventions for sites like TikTok, Netflix, and Reddit, sometimes even faking Chrome’s user agent. Chrome’s dominance forces minority browsers to compensate, echoing the IE era in reverse. #browser #interop

https://denodell.com/blog/browsers-treat-big-sites-differently

Soon we can finally banish JavaScript to the ShadowRealm. @Wilto walks through the TC39 ShadowRealm proposal, which creates isolated execution contexts with their own pristine globals while running on the same thread as the host. With just two methods, evaluate() and importValue(), ShadowRealms could sandbox third-party scripts, ads, and test suites without polluting the main realm. Currently at Stage 2.7, not yet in browsers. #js #ecmascript

https://css-tricks.com/soon-we-can-finally-banish-javascript-to-the-shadowrealm/

How to control infinite CSS animations. In part 1 of 2, @css shows how to speed up, slow down, and reverse infinite CSS animations on demand. He uses animation-composition: add to layer two animations, CSS variables for duration and a speed factor, and abs() and sign() functions to control velocity and direction independently, without restarting the animation. #css #animation

https://frontendmasters.com/blog/how-to-control-infinite-css-animations-part-1-of-2/

From React to native web with nanotags: a migration that saved 100 KB. Pavel Grinchenko explains how they migrated an Astro marketing site from React and Ark UI to native Web Components, cutting JavaScript by 100 KB. Nanotags is a sub-2.5 KB wrapper that adds validated props, typed refs, and automatic cleanup, plus reusable accessibility attachments for ARIA patterns. With nanostores, it covers dropdowns, modals, and toggles. #webcomponents #react

https://evilmartians.com/chronicles/from-react-to-native-web-with-nanotags-a-migration-that-saved-100kb

Recently, we fixed an unprecedented number of latent security bugs in Firefox identified by Claude Mythos Preview.

Here's how we approached this work, what we found, and what we learned:

https://hacks.mozilla.org/2026/05/behind-the-scenes-hardening-firefox/