sub Element

 

Module

The sub element is an inline element declared by the XHTML 1.1 Presentation Module (Inline Presentation)

Elements in the Presentation Module are:
big | small | sub | sup | i | b | tt (Inline Presentation Support Module)
hr (Block Presentation Support Module)

Description

The text within a sub element should be subscripted.

The same effect can be achieved using CSS using the declaration vertical-align:sub if you wish to separate content from presentation. I would generally use the sub tag if the subscripting were a semantic part of the text (such as the example above) and the CSS if it were desired for purely presentational reasons.

See also the sup element.

#REQUIRED Attributes

There are no #REQUIRED attributes on the sub element.

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Specific Attributes

There are no specific attributes declared on the sub element.

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Common Attributes

From the Core Attribute Collection

class [ type NMTOKENS ]

One or more space separated classes

id [ type ID ]

A unique identifier for the element

style [ type CDATA ], from the Style Attribute Module (deprecated)

Element-specific styles

title [ type Text ]

Descriptive title for the element (in some user agents this may appear as a "tooltip" when the mouse hovers over the element)

xmlns [ type URI - #FIXED 'http://www.w3.org/1999/xhtml' ]

XML namespace

From the I18N Attribute Collection

dir [ type Enumeration (ltr | rtl) ], from the Bi-directional Text Module

Left-to-right or right-to-left directionality

xml:lang [ type LanguageCode ]

A language code for the element

From the Events Attribute Collection

All attributes in the Events Attribute Collection are supported:
onclick, ondblclick, onmousedown, onmouseup, onmouseover, onmousemove, onmouseout, onkeypress, onkeydown, onkeyup

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Content Model

The Content Model for the sub element is:

( #PCDATA | Inline.mix )*

See Content Model & Nesting for information about Content Model syntax and Nesting Groups.

Valid children of sub

• #PCDATA
• From the Text Module: abbr, acronym, br, cite, code, dfn, em, kbd, q, samp, span, strong, var
• From the Hypertext Module: a
• From the Forms Module: button, input, label, select, textarea
• From the Images Module: img
• From the Presentation Module: b, big, i, small, sub, sup, tt
• From the Client-side Image Map Module: map
• From the Scripting Module: noscript, script
• From the Edit Module: del, ins
• From the Bi-directional Text Module: bdo
• From the Object Module: object
• From the Ruby Annotation Module: ruby

Valid parents of sub

• From the Text Module: abbr, acronym, address, cite, code, dfn, div, em, h1 - h6, kbd, p, q, samp, span, strong, var
• From the Hypertext Module: a
• From the List Module: dd, dt, li
• From the Tables Module: caption, td, th
• From the Forms Module: button, fieldset, label, legend
• From the Presentation Module: b, big, i, small, sub, sup, tt
• From the Edit Module: del, ins
• From the Bi-directional Text Module: bdo
• From the Object Module: object
• From the Ruby Annotation Module: rb, rt