Bi-directional Override

Support Key: [2|3|3.2|4] [X1|X1.1] [IE5B2|M|N6B1|O4]
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End Tag:
Standards Details:
In all HTML 4.x/XHTML DTDs
XHTML Modules:
Bi-directional Text
CSS 'display' Type:
CSS Mapping:
unicode-bidi, direction
Default Rendering:
Official Docs:
HTML 4.x, XHTML 1.1

What is it?
Many languages (including Latin alphabet based languages) are written and rendered horizontally from left to right, while some others (such as Arabic and Hebrew) are written and rendered from right to left. When characters from both writing systems are present, it is known as bi-directional text (also known as BIDI.) Some character combinations in BIDI situations are ambiguous with respect to the directionality of the content.

If the ambiguity is not made clear, it can be impossible for a computer to render these character combinations in such a way that the original meaning is conveyed. HTML has allowed for the resolution of this problem by creating the BDO element. This element is used to force the directionality of each character within to the value of its DIR attribute, irrespective of the characters' intrinsic directional properties. The BDO DIR attribute specifies whether the override is left-to-right or right-to-left.

BIDI override is needed where absolute control over character sequence order is required (such as mixed-language directionality words) and use of the common attribute DIR on other elements fails to produce proper bi-directional rendering. It is also useful in dealing with short pieces of text in which the directionality cannot be clearly resolved from the surrounding context.

Common Attributes
[2|3|3.2|4] [X1|X1.1] [IE5B2|M|N6B1|O4]
[2|3|3.2|4] [X1|X1.1] [IE5|M|N6|O5]
[2|3|3.2|4] [X1|X1.1] [IE5B2|M|N6B1|O4]
[2|3|3.2|4] [X1|X1.1] [IE5.5|M|N|O]

Specific Attributes
[2|3|3.2|4] [X1|X1.1] [IE5B2|M|N6.1|O]
Standards Details: In all HTML 4.x/XHTML DTDs
Required? Yes
On block-level elements, the DIR attribute indicates the base directionality of the text in the block. If omitted it is inherited from the parent element. The default directionality of the overall HTML document is left-to-right. On inline elements, it makes the element start a new directional embedding level. If omitted, the inline element does not start a new embedding level.
Values: ltr (Left to Right) | rtl (Right to Left)
[2|3|3.2|4] [X1|X1.1] [IE5B2|M|N6.1|O]
Standards Details: In all HTML 4.x/XHTML 1.0 DTDs. Dropped in XHTML 1.1 in favor of XML:Lang attribute.
Required? No
Specifies a string indicating the language/character set used in the BDO container.
Values: Any RFC 1766 value. [Must begin with a letter ([A-Za-z]), followed by any number of characters in [A-Za-z0-9-_:.]
Does this look <bdo dir="rtl">Backwards</bdo> to you?
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%In-line Content%
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