Re: [csswg-drafts] [css-text] Reconsider the initial value of the `text-autospace` property (#12386)

Hi, I am a Japanese researcher of CSS.

I have summarized my views on the pros and cons of ASCII spaces before and after Western text in HTML documents or plain text. It then gives its opinion as to what would be an appropriate initial value for the `text-autospace` property in this case.

https://qiita.com/debiru/items/1b4a5aa73fe5c952e104

Since I have written a blog post in Japanese, only the conclusions are reprinted here.

### The proper initial value for the CSS specification is `normal`.

In this case, we should consider what the ideal state is and whether there are any practical problems that would limit it, in that order, before finding a "realistic answer" to the question.

[[css-text-4] interscript text-spacing as default #8262](https://github.com/w3c/csswg-drafts/pull/8262) has determined the following as of 2022.

> Defines the interscript autospace to be 1/8 of the ideographic advance (0.125ic), which is the smallest amount in the common-use range. The primary justification for using 1/8 instead of 1/6 or 1/4 is that, since we're trying to make this the default, it minimizes the layout impact on existing pages. (Note that Antenna House uses a 1/4 default.)

There is no reason not to enable the `text-autospace` property by default, since the concrete values for character spacing are small to reduce the impact on existing web pages.

### The default value that most recent browsers should implement is `no-autospace`.

Looking at the comments on the GitHub Issue, some people have suggested that `no-autospace` should be the default value because of performance concerns.

Personally, if applying `text-autospace: normal` to a web page causes performance problems, I think we can conclude that `text-autospace: normal` is useless, not because of the initial value.

There should be a balance between providing a function that "adjusts the spacing between Japanese and Latin characters to make it easier to read" and "providing such a function without causing performance problems".

It would be a mistake to provide the `text-autospace` property when both of these features have not been met. If you do not want to use the `normal` value as the initial value because of concerns about performance issues, but you want to provide the `text-autospace` property itself, then I think that `no-autospace` is a realistic browser implementation of the text-autospace property as an initial value.

### What conclusions do you intend to draw on this topic?

> Forcing it on by default is a different topic. It means that we ignore authors who don't want the space. It means that we require users who don't want it to install extensions. It means that we don't care slowing down pages of other scripts, such as Arabic, Thai, Devanagari, etc.

I think you are confusing the question of "what should be the default value as a CSS specification" with the question of "what should be the default value for the most recently released browsers (Safari, Google Chrome) as of July 2025". Performance problems occur because of the algorithm used to implement it in the browser, not because of the `text-autospace` property itself.

If the functionality that the `text-autospace` property provides inherently has performance problems, then the `text-autospace` property should not be supported and should be eliminated from the CSS specification.

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Received on Sunday, 13 July 2025 14:00:06 UTC