offset-block-start

This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the specification changes.

Summary

The offset-block-start CSS property defines the logical block start offset of an element, which maps to a physical offset depending on the element's writing mode, directionality, and text orientation. It corresponds to the top, right, bottom, or left property depending on the values defined for writing-mode, direction, and text-orientation.

It relates to offset-block-end, offset-inline-start, and offset-inline-end, which define the other offsets of the element.

Initial value	`auto`
Applies to	positioned elements
Inherited	no
Percentages	logical-height of containing block
Media	visual
Computed value	same as box offsets: `top`, `right`, `bottom`, `left` properties except that directions are logical
Animation type	discrete
Canonical order	the unique non-ambiguous order defined by the formal grammar

Syntax

/* <length> values */
offset-block-start: 3px;
offset-block-start: 2.4em;

/* <percentage>s of the width or height of the containing block */
offset-block-start: 10%;

/* Keyword value */
offset-block-start: auto;

/* Global values */
offset-block-start: inherit;
offset-block-start: initial;
offset-block-start: unset;

Values

The offset-block-start property takes the same values as the left property.

Formal syntax

<'left'>

Example

HTML Content

<div>
  <p class="exampleText">Example text</p>
</div>

CSS Content

div {
  background-color: yellow;
  width: 120px;
  height: 120px;
}

.exampleText {
  writing-mode: vertical-lr;
  position: relative;
  offset-block-start: 20px;
  background-color: #c8c800;
}

Specification

Specification	Status	Comment
CSS Logical Properties Level 1 The definition of 'offset-block-start' in that specification.	Editor's Draft	Initial definition

Feature	Chrome	Firefox (Gecko)	Internet Explorer	Opera	Safari (WebKit)
Basic support	No support	41.0 (41.0)^[1]	No support	No support	No support

Feature	Android	Firefox Mobile (Gecko)	IE Phone	Opera Mobile	Safari Mobile
Basic support	No support	41.0 (41.0)^[1]	No support	No support	No support

[1] Available since Gecko 38, but behind the preference layout.css.vertical-text.enabled, then disabled by default. The preference has been removed in Gecko 51 and this property cannot be disabled since this version.

offset-block-start

Summary

Syntax

Values

Formal syntax

Example

HTML Content

CSS Content

Specification

Browser compatibility

See also

Document Tags and Contributors