- From: ExE Boss via GitHub <sysbot+gh@w3.org>
- Date: Thu, 25 Nov 2021 10:50:29 +0000
- To: public-css-archive@w3.org
Well, back when **WebKit** didn’t correctly support the **CSS2.1** syntax (before [r114876](https://commits.webkit.org/r114876)), they implemented support for surrogate pairs<sup>[mailing list](https://lists.w3.org/Archives/Public/www-style/2012Jan/0536.html)</sup> as a workaround.
---
> I'm not sure what the significance of your comment about CSS1 only allowing 4-digit escapes is, sorry.
The **CSS1** syntax for Unicode escapes<sup>[CSS1 Appendix B](https://www.w3.org/TR/CSS1/#appendix-b)</sup> in case‑insensitive flex<sup>[CSS1 ref16](https://www.w3.org/TR/CSS1/#ref16)</sup> notation is:
```flex
unicode \\[0-9a-f]{1,4}
```
Which means that anything after the 4th hex digit is not part of the escaped code point in **CSS1**:
```css
.foo:before {
/*
The "CSS1" specification parses this as:
- U+0000 (Null)
- U+0034 (Digit Four)
- U+0031 (Digit One)
The "CSS2.1" and "CSS Syntax Level 3" specifications parse this as:
- U+0041 (Latin Capital Letter A)
*/
content: "\000041";
}
```
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Received on Thursday, 25 November 2021 10:50:31 UTC