ruby-position

The ruby-position CSS property defines the position of a ruby element relative to its base element. It can be positioned over the element (over), under it (under), or between the characters on their right side (inter-character).

Try it

Syntax

css
/* Keyword values */
ruby-position: over;
ruby-position: under;
ruby-position: alternate;

/* Global values */
ruby-position: inherit;
ruby-position: initial;
ruby-position: revert;
ruby-position: revert-layer;
ruby-position: unset;

Values

over

Over example Is a keyword indicating that the ruby has to be placed over the main text for horizontal scripts and right to it for vertical scripts.

under

Under example Is a keyword indicating that the ruby has to be placed under the main text for horizontal scripts and left to it for vertical scripts.

alternate

Is a keyword indicating that the ruby alternates between over and under, when there are multiple levels of annotation.

Note: The specification also lists an additional value, inter-character, which is not currently supported in any browsers. When implemented, inter-character will behave as over in vertical writing modes. Otherwise, it indicates that the ruby has to be placed between the different characters, appearing on the right of the base in horizontal text and forcing the children of the ruby annotation container to have a vertical-rl writing mode.

Formal definition

Initial valuealternate
Applies toruby annotations containers
Inheritedyes
Computed valueas specified
Animation typediscrete

Formal syntax

ruby-position = 
  [ alternate || [ over | under ] ]  |
  inter-character

Examples

Ruby positioned over the text

HTML

html
<ruby>
  <rb>超電磁砲</rb>
  <rp>（</rp><rt>レールガン</rt><rp>）</rp>
</ruby>

CSS

css
ruby {
  ruby-position: over;
}

Result

Ruby positioned under the text

HTML

html
<ruby>
  <rb>超電磁砲</rb>
  <rp>（</rp><rt>レールガン</rt><rp>）</rp>
</ruby>

CSS

css
ruby {
  ruby-position: under;
}

Result

Ruby alternate

HTML

html
<ruby>
  <rb>A</rb><rb>B</rb><rb>C</rb>
  <rtc>Above</rtc>
  <rtc>Below</rtc>
</ruby>

CSS

css
ruby {
  ruby-position: alternate; /* this is also the initial value */
}

Result

Specifications

Specification
CSS Ruby Annotation Layout Module Level 1
# rubypos

Browser compatibility

BCD tables only load in the browser

See also