Jen Simmons
@jensimmons.bsky.social
Apple Evangelist on the Web Developer Experience team for Safari & Webkit. #PwME
We’ve been busy over here. For those asking about “stable” — yes, the work that’s currently in Safari Technology Preview will land in stable. Yup.
October 20, 2025 at 10:30 PM
We’ve been busy over here. For those asking about “stable” — yes, the work that’s currently in Safari Technology Preview will land in stable. Yup.
Interop 2025 is looking good!
October 20, 2025 at 7:53 PM
Interop 2025 is looking good!
Did you know that on macOS, you can update just to Safari 26, while remaining on macOS 15 Sequoia or even macOS 14 Sonoma?
Go to > System Settings > General > Software Update. Under “Also Available” you’ll find Safari listed. Click “Update Now”.
Go to > System Settings > General > Software Update. Under “Also Available” you’ll find Safari listed. Click “Update Now”.
September 16, 2025 at 7:03 PM
Did you know that on macOS, you can update just to Safari 26, while remaining on macOS 15 Sequoia or even macOS 14 Sonoma?
Go to > System Settings > General > Software Update. Under “Also Available” you’ll find Safari listed. Click “Update Now”.
Go to > System Settings > General > Software Update. Under “Also Available” you’ll find Safari listed. Click “Update Now”.
Want the tl;dr of the differences between the options?
May 1, 2025 at 2:59 PM
Want the tl;dr of the differences between the options?
To really understand what’s happening, try this demo in Safari Technology Preview 216.
cdpn.io/pen/debug/xx...
cdpn.io/pen/debug/xx...
April 8, 2025 at 2:43 PM
To really understand what’s happening, try this demo in Safari Technology Preview 216.
cdpn.io/pen/debug/xx...
cdpn.io/pen/debug/xx...
With Safari 18.4 shipping Ogg container support for both Opus and Vorbis, did Safari just pull into first place when it comes to media format support??
April 4, 2025 at 4:28 PM
With Safari 18.4 shipping Ogg container support for both Opus and Vorbis, did Safari just pull into first place when it comes to media format support??
My colleague @smfr.bsky.social has been working on this for many months, along with others including @nomster.bsky.social.
An early implementation is available in Safari Technology Preview after turning on the `corner-shape` flag — although it turned out to be more complex & not is done yet!
An early implementation is available in Safari Technology Preview after turning on the `corner-shape` flag — although it turned out to be more complex & not is done yet!
April 1, 2025 at 3:34 PM
My colleague @smfr.bsky.social has been working on this for many months, along with others including @nomster.bsky.social.
An early implementation is available in Safari Technology Preview after turning on the `corner-shape` flag — although it turned out to be more complex & not is done yet!
An early implementation is available in Safari Technology Preview after turning on the `corner-shape` flag — although it turned out to be more complex & not is done yet!
Today at the CSS Working Group "face to face" meeting…
Powerful tools for defining corner shapes. (Beyond the simple rounded corders you can do today with `border-radius`.)
Powerful tools for defining corner shapes. (Beyond the simple rounded corders you can do today with `border-radius`.)
April 1, 2025 at 3:30 PM
Today at the CSS Working Group "face to face" meeting…
Powerful tools for defining corner shapes. (Beyond the simple rounded corders you can do today with `border-radius`.)
Powerful tools for defining corner shapes. (Beyond the simple rounded corders you can do today with `border-radius`.)
It’s listed as a bug fix in the release notes, but we knew this fix is important enough to you and other web developers to also be described alongside all the other newly-available functionality.
April 1, 2025 at 12:39 PM
It’s listed as a bug fix in the release notes, but we knew this fix is important enough to you and other web developers to also be described alongside all the other newly-available functionality.
Does it bug you that Flexbox always ends up with a very few items in the last row, stretched out extra wide?
What if the layout was balanced kinda like `text-wrap`, using:
item-pack: balance;
Learn more about this idea, and much more:
webkit.org/blog/16587/i...
What if the layout was balanced kinda like `text-wrap`, using:
item-pack: balance;
Learn more about this idea, and much more:
webkit.org/blog/16587/i...
March 28, 2025 at 11:20 PM
Does it bug you that Flexbox always ends up with a very few items in the last row, stretched out extra wide?
What if the layout was balanced kinda like `text-wrap`, using:
item-pack: balance;
Learn more about this idea, and much more:
webkit.org/blog/16587/i...
What if the layout was balanced kinda like `text-wrap`, using:
item-pack: balance;
Learn more about this idea, and much more:
webkit.org/blog/16587/i...
There it is! Finally, a real solution for how to style all of the HTML form controls using your own custom CSS to change anything — building on an interoperable UA set of defaults.
First, styling the in-page part of controls + the popover for <select>. (Later we’ll do popovers for more things.)
First, styling the in-page part of controls + the popover for <select>. (Later we’ll do popovers for more things.)
March 21, 2025 at 11:21 PM
There it is! Finally, a real solution for how to style all of the HTML form controls using your own custom CSS to change anything — building on an interoperable UA set of defaults.
First, styling the in-page part of controls + the popover for <select>. (Later we’ll do popovers for more things.)
First, styling the in-page part of controls + the popover for <select>. (Later we’ll do popovers for more things.)
We heard your requests!
Responsive Design Mode in Safari 18.4 beta now has a dropdown of preset viewport sizes available. Along with a button to switch orientation.
Responsive Design Mode in Safari 18.4 beta now has a dropdown of preset viewport sizes available. Along with a button to switch orientation.
February 21, 2025 at 9:50 PM
We heard your requests!
Responsive Design Mode in Safari 18.4 beta now has a dropdown of preset viewport sizes available. Along with a button to switch orientation.
Responsive Design Mode in Safari 18.4 beta now has a dropdown of preset viewport sizes available. Along with a button to switch orientation.
Great question!
`item-pack: balance` (or maybe `item-wrap: balance`?) in Flexbox could do this… [see image].
Traditionally, Flexbox lays out each line without any regard for the other lines. This often results in a lonely stretched item or two in the last row. Yuk. Balance would balance that out.
`item-pack: balance` (or maybe `item-wrap: balance`?) in Flexbox could do this… [see image].
Traditionally, Flexbox lays out each line without any regard for the other lines. This often results in a lonely stretched item or two in the last row. Yuk. Balance would balance that out.
February 3, 2025 at 11:02 PM
Great question!
`item-pack: balance` (or maybe `item-wrap: balance`?) in Flexbox could do this… [see image].
Traditionally, Flexbox lays out each line without any regard for the other lines. This often results in a lonely stretched item or two in the last row. Yuk. Balance would balance that out.
`item-pack: balance` (or maybe `item-wrap: balance`?) in Flexbox could do this… [see image].
Traditionally, Flexbox lays out each line without any regard for the other lines. This often results in a lonely stretched item or two in the last row. Yuk. Balance would balance that out.
Working on new ideas for CSS — combine `flex-flow` + `grid-auto-flow` = space for new features…
• `item-pack: collapse` to create masonry-style layouts
• `item-pack: balance` to balance distribution of Flexbox items
• `item-wrap: nowrap` to put all items on one line in Grid
Thoughts?
• `item-pack: collapse` to create masonry-style layouts
• `item-pack: balance` to balance distribution of Flexbox items
• `item-wrap: nowrap` to put all items on one line in Grid
Thoughts?
February 3, 2025 at 10:04 PM
Working on new ideas for CSS — combine `flex-flow` + `grid-auto-flow` = space for new features…
• `item-pack: collapse` to create masonry-style layouts
• `item-pack: balance` to balance distribution of Flexbox items
• `item-wrap: nowrap` to put all items on one line in Grid
Thoughts?
• `item-pack: collapse` to create masonry-style layouts
• `item-pack: balance` to balance distribution of Flexbox items
• `item-wrap: nowrap` to put all items on one line in Grid
Thoughts?
I know you might have been busy with the holidays. Did you read about the new web technology in Safari 18.2?
If you make websites, what do you think about it?
webkit.org/blog/16301/w...
If you make websites, what do you think about it?
webkit.org/blog/16301/w...
January 23, 2025 at 11:11 PM
I know you might have been busy with the holidays. Did you read about the new web technology in Safari 18.2?
If you make websites, what do you think about it?
webkit.org/blog/16301/w...
If you make websites, what do you think about it?
webkit.org/blog/16301/w...
Did you notice that WebKit’s issue tracker got a facelift recently? Modern interface! Light and dark mode! Works on all sizes of screens! And you can even sign-in with a GitHub account now, instead of making a new account just for this site. We hope this makes it much easier to use.
bugs.webkit.org
bugs.webkit.org
January 16, 2025 at 8:12 PM
Did you notice that WebKit’s issue tracker got a facelift recently? Modern interface! Light and dark mode! Works on all sizes of screens! And you can even sign-in with a GitHub account now, instead of making a new account just for this site. We hope this makes it much easier to use.
bugs.webkit.org
bugs.webkit.org
How weird. I have no idea what I did. Here’s an even more fixed up version:
January 7, 2025 at 8:12 PM
How weird. I have no idea what I did. Here’s an even more fixed up version:
Looking at the Interop Project scores since 2021 — look at how much higher the overall “interop” score (the black line) is for 2024 over the previous years! Wow.
Great job everyone who was involved in 2024, from those who helped plan to those who fixed browser bugs or implemented new features.
Great job everyone who was involved in 2024, from those who helped plan to those who fixed browser bugs or implemented new features.
January 7, 2025 at 6:01 PM
Looking at the Interop Project scores since 2021 — look at how much higher the overall “interop” score (the black line) is for 2024 over the previous years! Wow.
Great job everyone who was involved in 2024, from those who helped plan to those who fixed browser bugs or implemented new features.
Great job everyone who was involved in 2024, from those who helped plan to those who fixed browser bugs or implemented new features.
I just made an interactive demo so you can compare the differences between `margin-block: 1lh` and `1em`. Turn on the guides to see the edges of the paragraphs vs what’s margin. And try out `margin-trim` in Safari to see what that does!
codepen.io/jensimmons/f...
codepen.io/jensimmons/f...
December 19, 2024 at 5:21 PM
I just made an interactive demo so you can compare the differences between `margin-block: 1lh` and `1em`. Turn on the guides to see the edges of the paragraphs vs what’s margin. And try out `margin-trim` in Safari to see what that does!
codepen.io/jensimmons/f...
codepen.io/jensimmons/f...
`margin-block: 1lh;` is such a better default for paragraphs of text than `margin-block: 1em;`
I highly recommend it.
I highly recommend it.
December 19, 2024 at 3:58 PM
`margin-block: 1lh;` is such a better default for paragraphs of text than `margin-block: 1em;`
I highly recommend it.
I highly recommend it.
Cleaning & organizing everything I own, yesterday I found a box of things I had no idea was on the very top shelf of a closet. In it, I found my two An Event Apart lunchboxes featuring @zeldman.bsky.social and @meyerweb.com!!! I was so happy to find them.
I miss An Event Apart. What a conference.
I miss An Event Apart. What a conference.
December 19, 2024 at 3:09 PM
Cleaning & organizing everything I own, yesterday I found a box of things I had no idea was on the very top shelf of a closet. In it, I found my two An Event Apart lunchboxes featuring @zeldman.bsky.social and @meyerweb.com!!! I was so happy to find them.
I miss An Event Apart. What a conference.
I miss An Event Apart. What a conference.
Safari 18.2 is here! For web developers, it’s the biggest release of new features this year. Highlights include cross-document View Transitions, text-box, spatial videos in visionOS, ruby improvements, WASM garbage collection, HTTPS by default, Genmoji, and more.
webkit.org/blog/16301/w...
webkit.org/blog/16301/w...
December 11, 2024 at 6:35 PM
Safari 18.2 is here! For web developers, it’s the biggest release of new features this year. Highlights include cross-document View Transitions, text-box, spatial videos in visionOS, ruby improvements, WASM garbage collection, HTTPS by default, Genmoji, and more.
webkit.org/blog/16301/w...
webkit.org/blog/16301/w...
Just look at that Interop 2024 score…
wpt.fyi/interop-2024
wpt.fyi/interop-2024
November 22, 2024 at 6:28 PM
Just look at that Interop 2024 score…
wpt.fyi/interop-2024
wpt.fyi/interop-2024