Liftoff News

Star City

Tue, 03 Jun 2003 09:39:21 GMT

How do Americans get ready to work with Russians aboard the International Space Station? They take a crash course in culture, language and protocol at Russia's Star City.

Fri, 30 May 2003 11:06:42 GMT

Sky watchers in Europe, Asia, and parts of Alaska and Canada will experience a partial eclipse of the Sun on Saturday, May 31st.

The Engine That Does More

Tue, 27 May 2003 08:37:32 GMT

Before man travels to Mars, NASA hopes to design new engines that will let us fly through the Solar System more quickly. The proposed VASIMR engine would do that.

Astronauts' Dirty Laundry

Tue, 20 May 2003 08:56:02 GMT

Compared to earlier spacecraft, the International Space Station has many luxuries, but laundry facilities are not one of them. Instead, astronauts have other options.

This month in Servo: new elements, IME support, delegate API, and more!

2025-03-10T00:00:00Z

Servo now supports more HTML and CSS features:

the <details> element (@simonwuelker, #35261)
the <meter> element (@simonwuelker, #35524)
the <progress> element (@simonwuelker, #35531)
the ‘quotes’ property (@xiaochengh, @Loirooriol, #34770, #35420)
the ‘isolation’ property (@kkoyung, @Loirooriol, #35552)
‘overflow: clip’ (@longvatrong111, #35103)
‘overflow’ property with two values (@yezhizhen, @mrobinson, #35414)
the ‘::slotted’ selector (@simonwuelker, #35352)

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Plus several new web API features:

contextmenu events (@pewsheen, #35364)
WritableStream (@gterzian, @jdm, #34844)
ReadableStreamBYOBRequest (@Taym95, #35074)
initial support for FontFace and its load() method (@mukilan, #35262)
toBlob() and toDataURL() on WebGPU canvases (@sagudev, #35237)
bytes() on Request, Response, and Blob (@shanehandley, @yoseio, @gterzian, @Taym95, #35250, #35151)
href, origin, protocol, username, password, host, hostname, port, pathname, search, and hash properties on HTMLAreaElement (@shanehandley, #35482)
insertRule() with no argument on CSSGroupingRule (@Loirooriol, #35295)

<slot> elements are now fully supported including layout (@simonwuelker, #35220, #35519), and we’ve also landed support for the ‘::slotted’ selector (@simonwuelker, #35352). -Shadow roots are now supported in devtools (@simonwuelker, #35294), and we’ve fixed some bugs related to shadow DOM trees (@simonwuelker, #35276, #35338), event handling (@simonwuelker, #35380), and custom elements (@maxtidev, @jdm, #35382).

We’ve landed layout improvements around ‘border-collapse’ (@Loirooriol, #35219), ‘align-content: normal’ (@rayguo17, #35178), ‘place-self’ with ‘position: absolute’ (@Loirooriol, #35208), the intrinsic sizing keywords (@Loirooriol, #35413, #35469, #35471, #35630, #35642, #35663, #35652, #35688), and ‘position: absolute’ now works correctly in a ‘position: relative’ grid item (@stevennovaryo, #35014).

Input has also been improved, with better IME support (@dklassic, #35535, #35623) and several fixes to touch input (@kongbai1996, @jschwe, @shubhamg13, #35450, #35031, #35550, #35537, #35692).

Servo-the-browser (servoshell) - -

Directory listings are now enabled for local files (@mrobinson, #35317).

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servoshell’s dialogs now use egui (@chickenleaf, #34823, #35399, #35464, #35507, #35564, #35577, #35657, #35671), rather than shelling out to a program like zenity (@chickenleaf, #35674), making them more secure and no longer falling back to terminal input.

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We’ve also fixed a bug when closing a tab other than the current one (@pewsheen, #35569).

Servo-the-engine (embedding) - -

We’ve simplified our embedding API by merging all input event delivery into WebView::notify_input_event (@mrobinson, @mukilan, #35430), making bluetooth optional (@jdm, @webbeef, #35479, #35590), making the “background hang monitor” optional (@jdm, #35256), and eliminating the need to depend on webxr (@mrobinson, #35229). -We’ve also moved some servoshell-only options out of Opts (@mrobinson, #35377, #35407), since they have no effect on Servo’s behaviour.

We’ve landed our initial delegate-based API (@delan, @mrobinson, @mukilan, #35196, #35260, #35297, #35396, #35400, #35544, #35579, #35662, #35672), which replaces our old message-based API for integrating Servo with your app (@mrobinson, @delan, @mukilan, #35284, #35315, #35366). -By implementing WebViewDelegate and ServoDelegate and installing them, you can have Servo call back into your app’s logic with ease.

We’ve simplified the RenderingContext trait (@wusyong, @mrobinson, #35251, #35553) and added three built-in RenderingContext impls (@mrobinson, @mukilan, #35465, #35501), making it easier to set up a context Servo can render to:

WindowRenderingContext renders to a whole window
OffscreenRenderingContext renders to part of a window
SoftwareRenderingContext renders to an image, without hardware acceleration

We’ve heavily reworked and documented our webview rendering model (@mrobinson, @wusyong, @mukilan, #35522, #35621), moved image output and shutdown logic out of the compositor (@mrobinson, @wusyong, #35538), and removed some complicated logic around synchronous repaints when a window is resized (@mrobinson, #35283, #35277). -These changes should make it a lot clearer how to get Servo’s webviews onto your display.

One part of this model that we’re starting to move away from is the support for multiple webviews in one rendering context (@mrobinson, @wusyong, #35536). -First landed in #31417, this was an expedient way to add support for multiple webviews, but it imposed some serious limitations on how webviews could be interleaved with other app content, and the performance and security was inadequate.

We’ve updated our winit_minimal example to take advantage of these changes (@webbeef, #35350, #35686), simplify it further (@robertohuertasm, #35253), and fix window resizing (@webbeef, #35691).

Perf and stability - -

The compositor now notifies the embedder of new frames immediately (@mrobinson, #35369), not via the constellation thread.

Servo’s typical memory usage has been reduced by over 1% thanks to Node object optimisations (@webbeef, #35592, #35554), and we’ve also improved our memory profiler (@webbeef, #35618, #35607).

We’ve fixed a bug causing very high CPU usage on sites like wikipedia.org (@webbeef, #35245), as well as bugs affecting requestAnimationFrame (@mukilan, #35387, #35435).

You can now configure our tracing-based profiler (--features tracing) with servo --tracing-filter instead of SERVO_TRACING (@jschwe, #35370).

We’ve continued reducing our use of unsafe in script (@nscaife, @stephenmuss, #35351, #35360, #35367, #35411), and moving parts of script to script_bindings (@jdm, #35279, #35280, #35292, #35457, #35459, #35578, #35620). -Breaking up our massive script crate is absolutely critical for reducing Servo’s build times.

We’ve fixed crashes that happen when moving windows past the edge of your monitor (@webbeef, #35235), when unpaired UTF-16 surrogates are sent to the DOM (@mrobinson, #35381), when focusing elements inside shadow roots (@simonwuelker, #35606), and when calling getAsString() on a DataTransferItem (@Gae24, #35699). -We’ve also continued working on static analysis that will help catch crashes due to GC borrow hazards (@augustebaum, @yerke, @jdm, @Gae24, #35541, #35593, #35565, #35610, #35591, #35609, #35601, #35596, #35595, #35594, #35597, #35622, #35604, #35616, #35605, #35640, #35647, #35646).

Donations - -

Thanks again for your generous support! -We are now receiving 4363 USD/month (+13.7% over January) in recurring donations. -This helps cover the cost of our self-hosted CI runners and Outreachy internships.

Servo is also on thanks.dev, and already 21 GitHub users (+5 over January) that depend on Servo are sponsoring us there. -If you use Servo libraries like url, html5ever, selectors, or cssparser, signing up for thanks.dev could be a good way for you (or your employer) to give back to the community.

4363 USD/month

10000

- -

As always, use of these funds will be decided transparently in the Technical Steering Committee. -For more details, head to our Sponsorship page.

- -

Servo Security Report: findings and solutions

2025-02-26T00:00:00Z

The Servo project has received several grants from NLnet Foundation, and as part of these grants, NLnet offers different support services. These services include security audits from Radically Open Security.

In one of our projects with NLnet, we were working on adding support for CSS floats and tables in Servo. Once the project was completed, we reached out to Radically Open Security to run a security audit. The focus of the audit was in the code related to that project, so the main components investigated were the CSS code paths in the layout engine and Stylo. As part of this audit, four vulnerabilities were identified:

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

ID	Type	Description	Threat level
`CLN-009`	Third-Party Library Vulnerability	Servo uses an outdated version of the time crate that is vulnerable to a known issue.	Moderate
`CLN-004`	Arithmetic underflow	By calling methods on a TableBuilder object in a specific order, an integer underflow can be triggered, followed by an attempted out-of-bounds access, which is caught by Rust, resulting in a panic.	Low
`CLN-002`	Arithmetic underflow	An arithmetic underflow condition is currently impossible to trigger, but may become accessible as its surrounding logic evolves.	N/A
`CLN-007`	Unguarded casting	Casting from an unsigned platform pointer-width integer into a fixed-width signed integer may result in erroneous layouts.	N/A

If you want to know more details you can read the full report.

The first issue (CLN-009) was related to a known vulnerability in version 0.1 of the time crate that Servo depended on (RUSTSEC-2020-0071). We had removed this in most of Servo, but there was one remaining dependency in WebRender. We have since addressed this vulnerability by removing it from the version of WebRender used in Servo (@mrobinson, #35325), and we will also try to upstream our changes so that Firefox is unaffected.

We have also fixed the second (CLN-004) and third (CLN-002) issues by making the affected code more robust (@Loirooriol, #34247, #35437), in the event web content can trigger them.

The fourth issue (CLN-007) is not urgent, since the values are constrained elsewhere and it would otherwise only affect layout correctness and not security, but it’s worth fixing at some point too.

Servo has long been highlighted for being a memory-safe and concurrency-safe web rendering engine, thanks to the guarantees provided by the Rust programming language, including its ownership system, borrow checker, and built-in data structures that enable safe concurrent programming. These features help prevent memory and concurrency vulnerabilities, such as use-after-free bugs and data races.

We find it promising that this security audit, although smaller and of limited scope, identified no severe vulnerabilities, especially none of that nature, and that we were able to address any vulnerabilities identified. This was a positive experience for Servo and the web, and we’re keen to explore more security auditing for Servo in the future.

Thanks to the folks at Radically Open Security for their work on this audit, and NLnet Foundation for continuously supporting the Servo project.

This month in Servo: new webview API, relative colors, canvas buffs, and more!

2025-02-19T00:00:00Z

Servo now supports several new web API features:

:host selector (@simonwuelker, #34870)
<slot> elements in the DOM (@simonwuelker, #35013, #35177, #35191, #35221, #35137, #35222), with layout support landing next month
Relative CSS colors, like color(from …) and rgb(from …) (@Loirooriol, #34897)
ClipboardEvent (@Gae24, #33576, #35146), with --pref dom_clipboardevent_enabled
Detecting WGSL extensions via WGSLLanguageFeatures (@sagudev, #34928)
pointer_composite_access WGSL extension (@sagudev, #35161)
blitFramebuffer() on WebGL2RenderingContext (@jdm, Istvan, #26389)
media property on HTMLStyleElement (@webbeef, #35148)

We’ve landed a bunch of HTMLCanvasElement improvements:

toDataURL() now supports image/jpeg and image/webp (@webbeef, #34861)
toBlob() is now supported (@webbeef, #34938)
transferControlToOffscreen() is now supported (@webbeef, #34959)

- " /> - -

Streams are a lot more useful now, with ReadableStreamBYOBReader now supporting read() (@Taym95, #35040), cancel(), close(), and releaseLock() (@Taym95, #34958).

Servo now passes 40.6% (+7.5pp) of enabled Shadow DOM tests, thanks to our landing support for the :host selector (@simonwuelker, #34870) and the <slot> element (@simonwuelker, #35013, #35177, #35191, #35221, #35137, #35222), plus improvements to event handling (@simonwuelker, #34788, #34884), script (@willypuzzle, #34787), style (@simonwuelker, @jdm, #35198, #35132), and the DOM tree (@simonwuelker, @Taym95, #34803, #34834, #34863, #34909, #35076).

Table layout is significantly better now, particularly in ‘table-layout: fixed’ (@Loirooriol, #35170), table sizing (@Loirooriol, @mrobinson, #34889, #34947, #35167), rowspan sizing (@mrobinson, @Loirooriol, #35095), interaction with floats (@Loirooriol, #35207), and ‘border-collapse’ layout (@Loirooriol, #34932, #34908, #35097, #35122, #35165) and painting (@Loirooriol, #34933, #35003, #35100, #35075, #35129, #35163).

As a result, Servo now passes 90.2% (+11.5pp) of enabled CSS tables tests, and of the tests that are in CSS 2, we now pass more than Blink and WebKit! -We literally stood on the shoulders of giants here, because this would not have been possible without Blink’s robust table impl. -Despite their age, tables are surprisingly underspecified, so we also needed to report several spec issues along the way (@Loirooriol).

Embedding - -

Servo aims to be an embeddable web engine, but so far it’s been a lot harder to embed Servo than it should be.

For one, configuring and starting Servo is complicated. -We found that getting Servo running at all, even without wiring up input or handling resizes correctly, took over 200 lines of Rust code (@delan, @mrobinson, #35118). -Embedders (apps) could only control Servo by sending and receiving a variety of “messages” and “events”, and simple questions like “what’s the current URL?” were impossible to answer without keeping track of extra state in the app.

Contrast this with WebKitGTK, where you can write a minimal kiosk app with a fully-functional webview in under 50 lines of C. -To close that gap, we’ve started reworking our embedding API towards something more idiomatic and ergonomic, starting with the concept embedders care about most: the webview.

Our new webview API is controlled by calling methods on a WebView handle (@delan, @mrobinson, #35119, #35183, #35192), including navigation and user input. -Handles will eventually represent the lifecycle of the webview itself; if you have one, the webview is valid, and if you drop them, the webview is destroyed.

Servo needs to call into the embedder too, and here we’ve started replacing the old EmbedderMsg API with a webview delegate (@delan, @mrobinson, #35211), much like the delegates in Apple’s WebKit API. -In Rust, a delegate is a trait that the embedder can install its own impl for. -Stay tuned for more on this next month!

Embedders can now intercept any request, not just navigation (@zhuhaichao518, #34961), and you can now identify the webview that caused an HTTP credentials prompt (@pewsheen, @mrobinson, #34808).

Other embedding improvements include:

Adding a trait to allow for alternative rendering contexts that are better suited to certain applications (@dklassic, @wusyong, #35052, #34813, #34780)
Simplifying types used by consumers of libservo (@delan, @mrobinson, #35156)
Making it easier to build Servo without crown (@jdm, #35055)

Other changes - -

We’ve reworked Servo’s preferences system, making all prefs optional with reasonable defaults (@mrobinson, #34966, #34999, #34994). -As a result:

The names of all preferences have changed; see the Prefs docs for a list
Embedders no longer need a prefs.json resource to get Servo running
Some debug options were converted to preferences (@mrobinson, #34998)

Devtools now highlights console.log() arguments according to their types (@simonwuelker, #34810).

Servo’s networking is more efficient now, with the ability to cancel fetches for navigation that contain redirects (@mrobinson, #34919) and cancel fetches for <video> and <media> when the document is unloaded (@mrobinson, #34883). -Those changes also eliminate per-request IPC channels for navigation and cancellation respectively, and in the same vein, we’ve eliminated them for image loading too (@mrobinson, #35041).

We’ve continued splitting up our massive script crate (@jdm, #34359, #35157, #35169, #35172), which will eventually make Servo much faster to build.

A few crashes have been fixed, including when exiting Servo (@mukilan, #34917), when using the internal memory profiler (@jdm, #35058), and when running ResizeObserver callbacks (@willypuzzle, #35168).

For developers - -

We now run CI smoketests on OpenHarmony using a real device (@jschwe, @mukilan, #35006), increasing confidence in your changes beyond compile-time errors.

We’ve also tripled our self-hosted CI runner capacity (@delan, #34983, #35002), making concurrent Windows and macOS builds possible without falling back to the much slower GitHub-hosted runners.

Servo can’t yet run WebDriver-based tests on wpt.fyi, wpt.servo.org, or CI, because the servo executor for the Web Platform Tests does not support testdriver.js. -servodriver does, though, so we’ve started fixing test regressions with that executor with the goal of eventually switching to it (@jdm, #34957, #34997).

Donations - -

Thanks again for your generous support! -We are now receiving 3835 USD/month (−11.4% over December) in recurring donations. -With this money, we’ve been able to expand our capacity for self-hosted CI runners on Windows, Linux, and macOS builds, halving mach try build times from over an hour to under 30 minutes!

Servo is also on thanks.dev, and already 21 GitHub users (+5 over December) that depend on Servo are sponsoring us there. -If you use Servo libraries like url, html5ever, selectors, or cssparser, signing up for thanks.dev could be a good way for you (or your employer) to give back to the community.

3835 USD/month

10000

- -

As always, use of these funds will be decided transparently in the Technical Steering Committee. -For more details, head to our Sponsorship page.

Conference talks - -

Why Build a New Browser Engine in Rust? (slides) — Martin Robinson spoke about Servo’s unique benefits as a Rust-based browser and web engine, and how browser diversity can create a new renaissance for the web platform

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Servo in 2024: stats, features and donations

2025-01-31T00:00:00Z

Two years after the renewed activity on the project we can confirm that Servo is fully back.

If we ignore the bots, in 2024 we’ve had 129 unique contributors (+143% over 54 last year), landing 1,771 pull requests (+163% over 673), and that’s just in our main repo!

Including bots, the total number of PRs merged goes up to 2,674 (+144% over 1094). From all this work, 26% of the PRs were made by Igalia, 40% by other contributors and the rest by the bots (34%). This shows how the Servo community has been growing and becoming more diverse with new actors participating actively in the project.

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	2018	2019	2020	2021	2022	2023	2024
Merged PRs	1,188	986	669	118	65	776	1,771
Unique contributors	142	141	87	37	20	54	129
Average unique contributors per month	27.33	27.17	14.75	4.92	2.83	11.33	26.33

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Now let’s take a look to the data and chart above, which show the evolution since 2018 in number of merged PRs, unique contributors per year and average contributors per month (excluding bots). We can see the project is back to numbers of 2018 and 2019 when it was been developed in full speed!

It’s worth noting that Servo popularity keeps growing, with many folks realizing there has been new activity on the project last year, and we have more and more people interested in the project.

Servo GitHub stars haven't stopped growing, surpassing now 25K threshold.

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During 2024 Servo has been present in 8 events with 9 talks: FOSDEM, Open Source Summit North America, Seattle Rust user meetup, GOSIM Europe, Global Software Technology Summit, Linux Foundation Europe Member Summit, GOSIM China, Ubuntu Summit.

If we focus on development there has been many things moving forward during the year. Servo main dependencies (SpiderMonkey, Stylo and WebRender) have been upgraded, the new layout engine has kept evolving adding support for floats, tables, flexbox, fonts, etc. By the end of 2024 Servo passes 1,515,229 WPT subtests (79%). Many other new features have been under active development: WebGPU, Shadow DOM, ReadableStream, WebXR, … Servo now supports two new platforms: Android and OpenHarmony. And we have got the first experiments of applications using Servo as a web engine (like Tauri, Blitz, QtWebView, Cuervo, Verso and Moto).

In 2024 we have raised 33,632.64 USD with donations via Open Collective and GitHub Sponsors from 500 different people and organizations. Thank you all for supporting us!

With this money we have now 3 servers that provides self-hosted runners for Linux, macOS, and Windows reducing our build times from over an hour to under 30 minutes.

Talking about the future, the Servo TSC has been discussing the roadmap for 2025 which has been updated on the Servo’s wiki. We have many plans to keep Servo thriving with new features and improvements. Let’s hope for a great 2025!

This month in Servo: dark mode, keyword sizes, XPath, and more!

2025-01-10T00:00:00Z

Servo now supports dark mode (@arthmis, @lazypassion, #34532), respecting the platform dark mode in servoshell and ‘prefers-color-scheme’ (@nicoburns, #34423, stylo#93) on Windows and macOS.

- - -

MDN article for ‘prefers-color-scheme’ in dark mode (left) and light mode (right), with --pref dom.resize_observer.enabled.

- -

CSS transitions can now be triggered properly by script (@mrobinson, #34486), and we now support ‘min-height’ and ‘max-height’ on column flex containers (@Loirooriol, @mrobinson, #34450), ‘min-content’, ‘max-content’, ‘fit-content’, and ‘stretch’ in block layout (@Loirooriol, #34641, #34568, #34695), ‘stretch’ on replaced positioned elements (@Loirooriol, #34430), as well as ‘align-self: self-start’, ‘self-end’, ‘left’, and ‘right’ on positioned elements (@taniishkaaa, @Loirooriol, #34365).

Servo can now run Discord well enough to log in and read messages, though you can’t send messages yet. -To get this working, we landed some bare-bones AbortController support (@jdm, @syvb, #34519) and a WebSocket fix (@jdm, #34634). -Try it yourself with --pref dom.svg.enabled --pref dom.intersection_observer.enabled --pref dom.abort_controller.enabled!

- - -

We now support console.trace() (@simonwuelker, #34629), PointerEvent (@wusyong, #34437), and the clonable property on ShadowRoot (@simonwuelker, #34514). -Shadow DOM support continues to improve (@jdm, #34503), including very basic Shadow DOM layout (@mrobinson, #34701) when enabled via --pref dom.shadowdom.enabled.

script underwent (and continues to undergo) major rework towards being more reliable and faster to build. -We’ve landed better synchronisation for DOM tree mutations (@jdm, #34505) and continued work on splitting up the script crate (@jdm, #34366). -We’ve moved our ReadableStream support into Servo, eliminating the maintenance burden of a downstream SpiderMonkey patch (@gterzian, @wusyong, @Taym95, #34064, #34675).

The web platform guarantees that same-origin frames and their parents can synchronously observe resizes and their effects. -Many tests rely on this, and not doing this correctly made Servo’s test results much flakier than they could otherwise be. -We’ve made very good progress towards fixing this (@mrobinson, #34643, #34656, #34702, #34609), with correct resizing in all cases except when a same-origin frame is in another script thread, which is rare.

We now support enough of XPath to get htmx working (@vlindhol, #34463), when enabled via --pref dom.xpath.enabled.

- - -

Servo’s performance continues to improve, with layout caching for flex columns delivering up to 12x speedup (@Loirooriol, @mrobinson, #34461), many unnecessary reflows now eliminated (@mrobinson, #34558, #34599, #34576, #34645), reduced memory usage (@mrobinson, @Loirooriol, #34563, #34666), faster rendering for pages with animations (@mrobinson, #34489), and timers now operating without IPC (@mrobinson, #34581).

servoshell nightlies are up to 20% smaller (@atbrakhi, #34340), WebGPU is now optional at build time (@atbrakhi, #34444), and --features tracing no longer enables --features layout-2013 (@jschwe, #34515) for further binary size savings. -You can also limit the size of several of Servo’s thread pools with --pref threadpools.fallback_worker_num and others (@jschwe, #34478), which is especially useful on machines with many CPU cores.

We’ve started laying the groundwork for full incremental layout in our new layout engine, starting with a general layout caching mechanism (@mrobinson, @Loirooriol, #34507, #34513, #34530, #34586). -This was lost in the switch to our new layout engine, and without it, every time a page changes, we have to rerun layout from scratch. -As you can imagine, this is very, very expensive, and incremental layout is critical for performance on today’s highly dynamic web.

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Donations - -

Thanks again for your generous support! -We are now receiving 4329 USD/month (+0.8% over November) in recurring donations. -With this money, we’ve been able to cover our web hosting and self-hosted CI runners for Windows, Linux, and now macOS builds (@delan, #34868), halving mach try build times from over an hour to under 30 minutes! -Next month, we’ll be expanding our CI capacity further, all made possible thanks to your help.

Servo is also on thanks.dev, and already sixteen GitHub users that depend on Servo are sponsoring us there. -If you use Servo libraries like url, html5ever, selectors, or cssparser, signing up for thanks.dev could be a good way for you (or your employer) to give back to the community.

4329 USD/month

10000

- -

As always, use of these funds will be decided transparently in the Technical Steering Committee. -For more details, head to our Sponsorship page.

- -

This month in Servo: :is(), :where(), grid layout, parallel flexbox, and more!

2024-12-09T00:00:00Z

Servo now supports :is() and :where() selectors (@mrobinson, #34066), parallel layout for flexbox (@mrobinson, #34132), and experimentally, CSS grid layout (@nicoburns, @taniishkaa, #32619, #34352, #34421)! -To try our new grid layout support, run Servo with --pref layout.grid.enabled.

We’ve added support for two key Shadow DOM interfaces, the shadowRoot property on Element (@simonwuelker, #34306) and the innerHTML property on ShadowRoot (@simonwuelker, #34335).

We’ve also landed ‘justify-self’ on positioned elements (@chickenleaf, #34235), form submission with <input type=image> (@shanehandley, #34203), DataTransfer (@Gae24, #34205), the close() method on ImageBitmap (@simonwuelker, #34124), plus several new SubtleCrypto API features:

crypto.subtle.deriveKey() (@simonwuelker, #34185)
wrapKey() and unwrapKey() (@msub2, #34262)
“HMAC” algorithm in generateKey() (@simonwuelker, #34278), sign(), verify() (@simonwuelker, #34223), and deriveKey("get key length") (@simonwuelker, #34230)
“AES-GCM” algorithm in encrypt(), decrypt(), generateKey(), and importKey() (@simonwuelker, #34269)
“AES-KW” algorithm in generateKey(), importKey(), wrapKey(), and unwrapKey() (@msub2, #34262)
“PBKDF2” (@simonwuelker, #34164) and “HKDF” (@simonwuelker, #34200) algorithms in deriveBits()

On OpenHarmony, we’ve landed keyboard input and the IME (@jschwe, @jdm, @mukilan, #34188), touch fling gestures (@jschwe, @mrobinson, #33219), and additional CJK fallback fonts (@jschwe, #34410). -You can now build for OpenHarmony on a Windows machine (@jschwe, #34113), and build errors have been improved (@jschwe, #34267).

More engine changes - -

You can now scroll the viewport and scrollable elements with your pointer anywhere in the area, not just when hovering over actual content (@mrobinson, @mukilan, #34347). ---unminify-js, a very useful feature for diagnosing Servo bugs in real websites, now supports module scripts (@jdm, #34206).

We’ve fixed the behaviour of offsetLeft and offsetTop relative to <body> with ‘position: static’ (@nicoburns, @Loirooriol, #32761), which also required spec changes (@nicoburns, @Loirooriol, w3c/csswg-drafts#10549). -We’ve also fixed several layout bugs around:

‘object-fit’ when ‘aspect-ratio’ is set (@Loirooriol, #34413)
clientWidth and friends on floats and replaced inlines (@Loirooriol, #34083)
‘align-items’ and ‘align-self: stretch’ (@mrobinson, @Loirooriol, #34162)
main axis free space in flexbox (@mrobinson, #34150)
min- and max-content block sizes of replaced elements (@Loirooriol, #34284)
sizing of non-replaced positioned elements with ‘place-self’ (@taniishkaa, #34264)

The getClientRects() method on Element now correctly returns a DOMRectList (@chickenleaf, #34025).

Stylo has been updated to 2024-11-01 (@Loirooriol, #34322), and we’ve landed some changes to prepare our fork of Stylo for publishing releases on crates.io (@mrobinson, @nicoburns, #34332, #34353). -We’ve also made more progress towards splitting up our massive script crate (@jdm, @sagudev, #34357, #34356, #34163), which will eventually allow Servo to be built (and rebuilt) much faster.

Performance improvements - -

In addition to parallel layout for flexbox (@mrobinson, #34132), we’ve landed several other performance improvements:

faster layout for ‘column’ flex containers (@Loirooriol, @mrobinson, #34346)
faster caching of intrinsic sizes (@Loirooriol, #34384)
caching of font template matches (@mukilan, @mrobinson, #34325)
fixed warnings and memory leak when WebRender is running late (@mrobinson, @mukilan, #34305)

We’ve also landed some changes to reduce Servo’s binary size:

legacy layout is no longer built by default (@jschwe, #34290)
Servo no longer depends on sparkle, only glow and gleam (@sagudev, #33918, #34292)
Servo can now be built without WebXR support (@wusyong, @augustkline, @jdm, @sagudev, #34241, #34348)
servoshell can now be built without WebXR on OpenHarmony and Android (@jschwe, #34242), with more platforms to come
plus some progress towards a build-time feature flag for WebGPU (@atbrakhi, #34415)

Servo’s tracing-based profiling support (--features tracing-perfetto or tracing-hitrace) now supports filtering events via an environment variable (@delan, #34236, #34256), and no longer includes events from non-Servo crates by default (@delan, #34209). -Note that when the filter matches some span or event, it will also match all of its descendants for now, but this is a limitation we intend to fix.

Most of the events supported by the old interval profiler have been ported to tracing (@delan, #34238, #34337). -ScriptParseHTML and ScriptParseXML events no longer count the time spent doing layout and script while parsing, reducing them to more realistic times (@delan, #34273), while ScriptEvaluate events now count the time spent running scripts in timers, DOM event listeners, and many other situations (@delan, #34286), increasing them to more realistic times.

We’ve added new tracing events for display list building (@atbrakhi, #34392), flex layout, inline layout, and font loading (@delan, #34392). -This will help us diagnose performance issues around things like caching and relayout for ‘stretch’ in flex layout, shaping text runs, and font template creation.

For developers - -

Hacking on Servo is now easier, with our new --profile medium build mode in Cargo (@jschwe, #34035). -medium is more optimised than debug, but unlike release, it supports debuggers, line numbers in backtraces, and incremental builds.

Servo now uses CODEOWNERS to list reviewers that are experts in parts of our main repo. -This should make it much easier to find reviewers that know how to review your code, and helps us maximise the quality of our code reviews by allowing reviewers to specialise.

Donations - -

Thanks again for your generous support! -We are now receiving 4291 USD/month (+2.1% over October) in recurring donations. -We are no longer accepting donations on LFX — if you were donating there, please move your recurring donations to GitHub or Open Collective.

Servo is also on thanks.dev, and already fifteen GitHub users that depend on Servo are sponsoring us there. -If you use Servo libraries like url, html5ever, selectors, or cssparser, signing up for thanks.dev could be a good way for you (or your employer) to give back to the community.

4291 USD/month

10000

- -

With this money, we’ve been able to cover our web hosting and self-hosted CI runners for Windows and Linux builds. -When the time comes, we’ll also be able to afford macOS runners and perf bots, as well as additional Outreachy interns next year! -As always, use of these funds will be decided transparently in the Technical Steering Committee. -For more details, head to our Sponsorship page.

Conferences and blogs - -

Servo Revival: 2023-2024 — Manuel Rego wrote about Igalia’s role in getting Servo back to life, and now thriving, over the past two years
Porting Servo to OpenHarmony — Jonathan Schwender spoke at GOSIM China 2024 about the work we’ve done towards supporting OpenHarmony in Servo
Taming concurrency with (in)-formal methods in Servo — Gregory Terzian spoke at GOSIM China 2024 about using TLA+ to help us correctly implement concurrent algorithms like the HTML event loop in Servo

- -

Behind the code: an interview with msub2

2024-11-12T00:00:00Z

Behind the Code is a new series of interviews with the contributors who help propel Servo forward. Ever wondered why people -choose to work on web browsers, or how they get started? We invite you to look beyond the project’s pull requests and issue -reports, and get to know the humans who make it happen.

msub2 - -

Some representative contributions:

Tell us about yourself! - -

My name is Daniel, though I more commonly go by my online handle “msub2”. I’m something of a generalist, but my primary interests -are developing for the web, XR, and games. I created and run the WebXR Discord, which has members from both the Immersive Web Working -Group and the Meta Browser team, among others. In my free time (when I’m not working, doing Servo things, or tending to my other -programming projects) I’m typically watching videos from YouTube/Dropout/Nebula/etc and playing video games.

Why did you start contributing to Servo? - -

A confluence of interests, to put it simply. I was just starting to really get into Rust, having built a CHIP-8 emulator and an -NES emulator to get my hands dirty, but I also had prior experience contributing to other browser projects like Chromium and Gecko. -I was also eyeing Servo’s WebXR implementation (which I had submitted a couple small fixes for last year) as I could see there was -still plenty of work that could be done there. To get started though, I looked for an adjacent area that I could work on to get -familiar with the main Servo codebase, which led to my first contribution being support for non-XR gamepads!

What was challenging about your first contribution? - -

I’d say the most challenging part of my first contribution was twofold: the first was just getting oriented with how data flows -in and out of Servo via the embedding API and the second was understanding how DOM structs, methods, and codegen all worked together -in the script crate. Servo is a big project, but luckily I got lots of good help and feedback as I was working through it, which -definitely made things easier. Looking at existing examples in the codebase of the things I was trying to do got me the rest of the -way there I’d say.

What do you like about contributing to the project? What do you get out of it? - -

The thing I like most about Servo (and perhaps the web platform as an extension) is the amount of interesting problems that there -are to solve when it comes to implementing/supporting all of its different features. While most of my contributions so far have been -focused around Gamepad and WebXR, recently I’ve been working to help implement SubtleCrypto alongside another community member, which -has been really interesting! In addition to the satisfaction I get just from being able to solve interesting problems, I also rather -enjoy the feeling of contributing to a large, communal, open-source project.

- -

I’d encourage anyone who’s intrigued by the idea of contributing to Servo to give it a shot! The recent waves of attention for projects -like Verso and Ladybird have shown that there is an appetite for new browsers and browser engines, and with Servo’s history it just -feels right that it should finally be able to rise to a more prominent status in the ecosystem.

This month in Servo: faster fonts, fetches, and flexbox!

2024-11-08T00:00:00Z

Servo now supports ‘mix-blend-mode: plus-lighter’ (@mrobinson, #34057) and ‘transition-behavior: allow-discrete’ (@Loirooriol, #33991), including in the ‘transition’ shorthand (@Loirooriol, #34005), along with the fetch metadata request headers ‘Sec-Fetch-Site’, ‘Sec-Fetch-Mode’, ‘Sec-Fetch-User’, and ‘Sec-Fetch-Dest’ (@simonwuelker, #33830).

, ‘transition-behavior: allow-discrete’, ‘mix-blend-mode: plus-lighter’, and ‘width: stretch’" /> -

We now have partial support for the CSS size keywords ‘min-content’, ‘max-content’, ‘fit-content’, and ‘stretch’ (@Loirooriol, #33558, #33659, #33854, #33951), including in floats (@Loirooriol, #33666), atomic inlines (@Loirooriol, #33737), and elements with ‘position: absolute’ or ‘fixed’ (@Loirooriol, #33950).

We’re implementing the SubtleCrypto API, starting with full support for crypto.subtle.digest() (@simonwuelker, #34034), partial support for generateKey() with AES-CBC and AES-CTR (@msub2, #33628, #33963), and partial support for encrypt(), and decrypt() with AES-CBC (@msub2, #33795).

More engine changes - -

Servo’s architecture is improving, with a new cross-process compositor API that reduces memory copy overhead for video (@mrobinson, @crbrz, #33619, #33660, #33817). -We’ve also started phasing out our old OpenGL bindings (gleam and sparkle) in favour of glow, which should reduce Servo’s complexity and binary size (@sagudev, @mrobinson, surfman#318, webxr#248, #33538, #33910, #33911).

We’ve updated to Stylo 2024-10-04 (@Loirooriol, #33767) and wgpu 23 (@sagudev, #34073, #33819, #33635). -The new version of wgpu includes several patches from @sagudev, adding support for const_assert, as well as accessing const arrays with runtime index values. -We’ve also reworked WebGPU canvas presentation to ensure that we never use old buffers by mistake (@sagudev, #33613).

We’ve also landed a bunch of improvements to our DOM geometry APIs, with DOMMatrix now supporting toString() (@simonwuelker, #33792) and updating is2D on mutation (@simonwuelker, #33796), support for DOMRect.fromRect() (@simonwuelker, #33798), and getBounds() on DOMQuad now handling NaN correctly (@simonwuelker, #33794).

We now correctly handle non-ASCII characters in <img srcset> (@evuez, #33873), correctly handle data: URLs in more situations (@webbeef, #33500), and no longer throw an uncaught exception when pages try to use IntersectionObserver (@mrobinson, #33989).

Outreachy contributors are doing great work in Servo again, helping us land many of this month’s improvements to GC static analysis (@taniishkaa, @webbeef, @chickenleaf, @jdm, @jahielkomu, @wulanseruniati, @lauwwulan, #33692, #33706, #33800, #33774, #33816, #33808, #33827, #33822, #33820, #33828, #33852, #33843, #33836, #33865, #33862, #33891, #33888, #33880, #33902, #33892, #33893, #33895, #33931, #33924, #33917, #33921, #33958, #33920, #33973, #33960, #33928, #33985, #33984, #33978, #33975, #34003, #34002) and code health (@chickenleaf, @DileepReddyP, @taniishkaa, @mercybassey, @jahielkomu, @cashall-0, @tony-nyagah, @lwz23, @Noble14477, #33959, #33713, #33804, #33618, #33625, #33631, #33632, #33633, #33643, #33643, #33646, #33648, #33653, #33664, #33685, #33686, #33689, #33686, #33690, #33705, #33707, #33724, #33727, #33728, #33729, #33730, #33740, #33744, #33757, #33771, #33757, #33782, #33790, #33809, #33818, #33821, #33835, #33840, #33853, #33849, #33860, #33878, #33881, #33894, #33935, #33936, #33943).

Performance improvements - -

Our font system is faster now, with reduced latency when loading system fonts (@mrobinson, #33638), layout no longer blocking on sending font data to WebRender (@mrobinson, #33600), and memory mapped system fonts on macOS and FreeType platforms like Linux (@mrobinson, @mukilan, #33747).

Servo now has a dedicated fetch thread (@mrobinson, #33863). -This greatly reduces the number of IPC channels we create for individual requests, and should fix crashes related to file descriptor exhaustion on some platforms. -Brotli-compressed responses are also handled more efficiently, such that we run the parser with up to 8 KiB of decompressed data at a time, rather than only 10 bytes of compressed data at a time (@crbrz, #33611).

Flexbox layout now uses caching to avoid doing unnecessary work (@mrobinson, @Loirooriol, #33964, #33967), and now has experimental tracing-based profiling support (@mrobinson, #33647), which in turn no longer spams RUST_LOG=info when not enabled (@delan, #33845). -We’ve also landed optimisations in table layout (@Loirooriol, #33575) and in our layout engine as a whole (@Loirooriol, #33806).

Work continues on making our massive script crate build faster, with improved incremental builds (@sagudev, @mrobinson, #33502) and further patches towards splitting script into smaller crates (@sagudev, @jdm, #33627, #33665).

We’ve also fixed several crashes, including when initiating a WebXR session on macOS (@jdm, #33962), when laying out replaced elements (@Loirooriol, #34006), when running JavaScript modules (@jdm, #33938), and in many situations when garbage collection occurs (@chickenleaf, @taniishkaa, @Loirooriol, @jdm, #33857, #33875, #33904, #33929, #33942, #33976, #34019, #34020, #33965, #33937).

servoshell, embedding, and devtools - -

Devtools support (--devtools 6080) is now compatible with Firefox 131+ (@eerii, #33661), and no longer lists iframes as if they were inspectable tabs (@eerii, #34032).

Servo-the-browser now avoids unnecessary redraws (@webbeef, #34008), massively reducing its CPU usage, and no longer scrolls too slowly on HiDPI systems (@nicoburns, #34063). -We now update the location bar when redirects happen (@rwakulszowa, #34004), and these updates are sent to all embedders of Servo, not just servoshell.

We’ve added a new --unminify-css option (@Taym95, #33919), allowing you to dump the CSS used by a page like you can for JavaScript. -This will pave the way for allowing you to modify that CSS for debugging site compat issues, which is not yet implemented.

We’ve also added a new --screen-size option that can help with testing mobile websites (@mrobinson, #34038), renaming the old --resolution option to --window-size, and we’ve removed --no-minibrowser mode (@Taym95, #33677).

We now publish nightly builds for OpenHarmony on servo.org (@mukilan, #33801). -When running servoshell on OpenHarmony, we now display toasts when pages load or panic (@jschwe, #33621), and you can now pass certain Servo options via hdc shell aa start or a test app (@jschwe, #33588).

Donations - -

Thanks again for your generous support! -We are now receiving 4201 USD/month (+1.3% over September) in recurring donations. -We are no longer accepting donations on LFX — if you were donating there, please move your recurring donations to GitHub or Open Collective.

Servo is also on thanks.dev, and already ten GitHub users that depend on Servo are sponsoring us there. -If you use Servo libraries like url, html5ever, selectors, or cssparser, signing up for thanks.dev could be a good way for you (or your employer) to give back to the community.

4201 USD/month

10000

- -

With this money, we’ve been able to pay for a second Outreachy intern in this upcoming round, plus our web hosting and self-hosted CI runners for Windows and Linux builds. -When the time comes, we’ll also be able to afford macOS runners and perf bots! -As always, use of these funds will be decided transparently in the Technical Steering Committee. -For more details, head to our Sponsorship page.

Conference talks - -

Servo project update — Manuel Rego spoke at the LF Europe Member Summit about the status and long-term vision of the Servo project
Servo: Building a Browser Rendering Engine in Rust (slides) — Rakhi Sharma spoke at the Ubuntu Summit about Servo’s recent work in embedding, layout, and benchmarking

- -

This month in Servo: Android nightlies, right-to-left, WebGPU, and more!

2024-10-03T00:00:00Z

Servo has had several new features land in our nightly builds over the last month:

as of 2024-09-10, we now support <ul type> and <ul compact> (@simonwuelker, #33303)
as of 2024-09-10, we now support console.timeLog() (@simonwuelker, #33377)
as of 2024-09-10, we now support the encodeInto() method on TextEncoder (@webbeef, @mrobinson, #33360)
as of 2024-09-10, we now support <link rel=prefetch> (@simonwuelker, #33345)
as of 2024-09-12, we now support right-to-left languages, except for floats (@mrobinson, @atbrakhi, #33375)
as of 2024-09-14, we now support ‘table-layout: fixed’ (@Loirooriol, @mrobinson, #33384, #33442)
as of 2024-09-17, we now support the ‘reset’ event on XRReferenceSpace properties (@msub2, #33460)
as of 2024-09-19, we now support the ‘object-fit’ and ‘object-position’ properties (@mrobinson, @Loirooriol, #33479)
as of 2024-09-19, Crypto.getRandomValues() can now take BigInt64Array or BigUint64Array (@msub2, #33485)
as of 2024-09-25, we now support ‘innerText’ and ‘outerText’ on HTMLElement (@Melchizedek6809, @shanehandley, #33312)

, right-to-left layout, ‘table-layout: fixed’, ‘object-fit’, ‘object-position’, crypto.getRandomValues(BigInt64Array) and (BigUint64Array), and innerText and outerText" /> -

Servo’s flexbox support continues to mature, with support for ‘align-self: normal’ (@Loirooriol, #33314), plus corrections to cross-axis percent units in descendants (@Loirooriol, @mrobinson, #33242), automatic minimum sizes (@Loirooriol, @mrobinson, #33248, #33256), replaced flex items (@Loirooriol, @mrobinson, #33263), baseline alignment (@mrobinson, @Loirooriol, #33347), and absolute descendants (@mrobinson, @Loirooriol, #33346).

Our table layout has improved, with support for width and height presentational attributes (@Loirooriol, @mrobinson, #33405, #33425), as well as better handling of ‘border-collapse’ (@Loirooriol, #33452) and extra <col> and <colgroup> columns (@Loirooriol, #33451).

We’ve also started working on the intrinsic sizing keywords ‘min-content’, ‘max-content’, ‘fit-content’, and ‘stretch’ (@Loirooriol, @mrobinson, #33492). -Before we can support them, though, we needed to land patches to calculate intrinsic sizes, including for percent units (@Loirooriol, @mrobinson, #33204), aspect ratios of replaced elements (@Loirooriol, #33240), column flex containers (@Loirooriol, #33299), and ‘white-space’ (@Loirooriol, #33343).

We’ve also worked on our WebGPU support, with support for pipeline-overridable constants (@sagudev, #33291), and major rework to GPUBuffer (@sagudev, #33154) and our canvas presentation (@sagudev, #33387). -As a result, GPUCanvasContext now properly supports (re)configuration and resize on GPUCanvasContext (@sagudev, #33521), presentation is now faster, and both are now more conformant with the spec.

Performance and reliability - -

Servo now sends font data over shared memory (@mrobinson, @mukilan, #33530), saving a huge amount of time over sending font data over IPC channels.

We now debounce resize events for faster window resizing (@simonwuelker, #33297), limit document title updates (@simonwuelker, #33287), and use DirectWrite kerning info for faster text shaping on Windows (@crbrz, #33123).

Servo has a new kind of experimental profiling support that can send profiling data to Perfetto (on all platforms) and HiTrace (on OpenHarmony) via tracing (@atbrakhi, @delan, #33188, #33301, #33324), and we’ve instrumented Servo with this in several places (@atbrakhi, @delan, #33189, #33417, #33436). -This is in addition to Servo’s existing HTML-trace-based profiling support.

We’ve also added a new profiling Cargo profile that builds Servo with the recommended settings for profiling (@delan, #33432). -For more details on building Servo for profiling, benchmarking, and other perf-related use cases, check out our updated Building Servo chapter (@delan, book#22).

Build times - -

The first patch towards splitting up our massive script crate has landed (@sagudev, #33169), over ten years since that issue was first opened.

script is the heart of the Servo rendering engine — it contains the HTML event loop plus all of our DOM APIs and their bindings to SpiderMonkey, and the script thread drives the page lifecycle from parsing to style to layout. -script is also a monolith, with over 170 000 lines of hand-written Rust plus another 520 000 lines of generated Rust, and it has long dominated Servo’s build times to the point of being unwieldy, so it’s very exciting to see that we may be able to change this.

Contributors to Servo can now enjoy faster self-hosted CI runners for our Linux builds (@delan, @mrobinson, #33321, #33389), cutting a typical Linux-only build from over half an hour to under 8 minutes, and a typical T-full try job from over an hour to under 42 minutes.

We’ve now started exploring self-hosted macOS runners (@delan, ci-runners#3), and in the meantime we’ve landed several fixes for self-hosted build failures (@delan, @sagudev, #33283, #33308, #33315, #33373, #33471, #33596).

Beyond the engine - -

You can now download the Servo browser for Android on servo.org (@mukilan, #33435)! -servoshell now supports gamepads by default (@msub2, #33466), builds for OpenHarmony (@mukilan, #33295), and has better navigation on Android (@msub2, #33294).

Tabbed browsing on desktop platforms has become a lot more polished, with visible close and new tab buttons (@Melchizedek6809, #33244), key bindings for switching tabs (@Melchizedek6809, #33319), as well as better handling of empty tab titles (@Melchizedek6809, @mrobinson, #33354, #33391) and the location bar (@webbeef, #33316).

We’ve also fixed several HiDPI bugs in servoshell (@mukilan, #33529), as well as keyboard input and scrolling on Windows (@crbrz, @jdm, #33225, #33252).

Donations - -

Thanks again for your generous support! -We are now receiving 4147 USD/month (+34.7% over August) in recurring donations. -This includes donations from 12 people on LFX, but we will stop accepting donations there soon — please move your recurring donations to GitHub or Open Collective.

Servo is also on thanks.dev, and already eleven GitHub users that depend on Servo are sponsoring us there. -If you use Servo libraries like url, html5ever, selectors, or cssparser, signing up for thanks.dev could be a good way for you (or your employer) to give back to the community.

4147 USD/month

10000

- -

With this money, we’ve been able to pay for our web hosting and self-hosted CI runners for Windows and Linux builds, and when the time comes, we’ll be able to afford macOS runners, perf bots, and maybe even an Outreachy intern or two! -As always, use of these funds will be decided transparently in the Technical Steering Committee. -For more details, head to our Sponsorship page.

- -

Reviving the devtools support in Servo

2024-09-20T00:00:00Z

The HTML and CSS inspector is able to display the DOM elements and their attributes and CSS properties.

Servo has been working on improving our Firefox devtools support as part of the Outreachy internship program since June, and we’re thrilled to share significant progress.

Devtools are a set of browser web developer tools that allows you to examine, edit, and debug HTML, CSS, and JavaScript. -Servo leverages existing work from the Firefox devtools to inspect its own websites, employing the same open protocol that is used for connecting to other Firefox instances.

While relying on a third party API allows us to offer this functionality without building it from scratch, it doesn’t come without downsides. -Back in June last year, with the release of Firefox 110, changes to the protocol broke our previous implementation. -The core issue was that the message structure sent between Servo and Firefox for the devtools functionality had changed.

To address this, we first updated an existing patch to fix the connection and list the webviews running in Servo (@fabricedesre, @eerii, @mrobinson, #32475). -We also had to update the structure of some actors (pieces of code that respond to messages sent by Firefox with relevant information), since they changed significantly (@eerii, #32509).

One of the main challenges was figuring out the messages we needed to send back to Firefox. -The source code for their devtools implementation is very well commented and proved to be invaluable. -However, it was also helpful to see the actual messages being sent. -While Servo can show the ones it sends and receives, debugging another instance of Firefox to observe its messages was very useful. -To facilitate this, we made a helper script (@eerii, #32684) using Wireshark to inspect the connection between the devtools client and server, allowing us to view the contents of each packet and search through them.

Support for the console was fixed, enabling the execution of JavaScript code directly in Servo’s webviews and displaying any warnings or errors that the page emits (@eerii, @mrobinson, #32727).

The JavaScript developer console now displays page logs. -It can also run commands.

Finally, the most significant changes involved the DOM inspector. -Tighter integration with Servo’s script module was required to retrieve the properties of each element. -Viewing CSS styles was particularly challenging, since they can come from many places, including the style attribute, a stylesheet, or from ancestors, but @emilio had great insight into where to look. -As a result, it’s now possible to view the HTML tree, and add, remove, or modify any attribute or CSS property (@eerii, @mrobinson, #32655, #32884, #32888, #33025).

There is still work to be done. -Some valuable features like the Network and Storage tabs are still not functional, and parts of the DOM inspector are still barebones. -For example, now that flexbox is enabled by default (@mrobinson, #33186), it would be a good idea to support it in the Layout panel. -We’re working on developer documentation that will be available in the Servo book to make future contributions easier.

That said, the Console and Inspector support has largely landed, and you can enable them with the --devtools flag in servoshell. -For a step-by-step guide on how to use Servo’s devtools, check out the new devtools chapter in the Servo book. -We’d love to hear your feedback on how these work and what additional features you’d find helpful in your workflow.

Many thanks to @eerii and Outreachy for the internship that made this possible!

- -

Liftoff News

Star City

The Engine That Does More

Astronauts' Dirty Laundry

This month in Servo: new elements, IME support, delegate API, and more!

Servo-the-browser (servoshell) - -

Servo-the-engine (embedding) - -

Perf and stability - -

Donations - -

Servo Security Report: findings and solutions

This month in Servo: new webview API, relative colors, canvas buffs, and more!

Embedding - -

Other changes - -

For developers - -

Donations - -

Conference talks - -

Servo in 2024: stats, features and donations

This month in Servo: dark mode, keyword sizes, XPath, and more!

Donations - -

This month in Servo: :is(), :where(), grid layout, parallel flexbox, and more!

More engine changes - -

Performance improvements - -

For developers - -

Donations - -

Conferences and blogs - -

Behind the code: an interview with msub2

msub2 - -

Tell us about yourself! - -

Why did you start contributing to Servo? - -

What was challenging about your first contribution? - -

What do you like about contributing to the project? What do you get out of it? - -

Any final thoughts you’d like to share? - -

This month in Servo: faster fonts, fetches, and flexbox!

More engine changes - -

Performance improvements - -

servoshell, embedding, and devtools - -

Donations - -

Conference talks - -

This month in Servo: Android nightlies, right-to-left, WebGPU, and more!

Performance and reliability - -

Build times - -

Beyond the engine - -

Donations - -

Reviving the devtools support in Servo