CSS: “text-autospace”: X is not a “text-autospace” value.

The text-autospace declaration uses a value the CSS standard does not define, most often none, which the standard calls no-autospace.

text-autospace controls the extra space a browser adds where Chinese, Japanese or Korean (CJK) characters meet Latin letters or digits. CSS Text Module Level 4 accepts normal, auto, no-autospace, or a combination of ideograph-alpha, ideograph-numeric and punctuation, optionally followed by insert or replace. The validator rejects any other value.

The none value usually comes from Microsoft Word, which writes text-autospace: none into the inline styles of the text it exports or copies. The declaration survives when that text is pasted into a CMS editor. It is a leftover from Internet Explorer's version of the property, whose ideograph-parenthesis and ideograph-space values are not standard either.

Browsers drop a declaration with an unknown value, so text-autospace: none has no effect and you can delete it without changing how the page looks. If the text mixes CJK and Latin characters and you want the spacing turned off, write no-autospace instead.

Invalid example

<p style="text-autospace: none;">Annual report 2026</p>

Valid example

Delete the declaration:

<p>Annual report 2026</p>

Or, to keep the spacing off in CJK text, use the standard keyword:

<p lang="ja" style="text-autospace: no-autospace;">HTML5とCSS3の基本</p>

Learn more:

MDN Reference

MDN Web Docs: text-autospace

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W3C Reference

CSS Text Module Level 4

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