HTML <sub> Tag for Subscripts


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The <sub> Tag in HTML 5

The <sub> tag creates subscript text. The sub element is one of the phrase elements in HTML. The content of the sub element is displayed below the normal baseline level. The <sup> tag performs a similar function except that the content is displayed above the normal baseline level.

An alternative to the <sub> tag is the vertical-align: sub CSS style property. The vertical-align: super style raises the applicable content above the normal baseline level.

<sub> Tag Syntax

   ... phrasing content expected ...<sub>... phrasing content ...</sub>
Rules for coding the HTML sub element

Make sure you understand the difference between a tag and element and are familiar with the definitions of namespace and other HTML terms.

  1. Code the sub element for subscript text where phrasing content is expected.
  2. Begin the sub element with a starting <sub> tag. The element name uses lower case letters and should be in the HTML namespace, which it will pick up automatically from the xmlns attribute on the <html> tag.
  3. Include any HTML global attributes on the <sub> tag as appropriate.
  4. Inside the sub element, between the starting <sub> tag and the ending </sub> tag, code the inner HTML phrasing content.
  5. End the sub element with a matching </sub> closing tag.
Content Model
Content of the sub element

The content of the sub element can include HTML comments, text content and only those HTML tags that can be used in phrasing content.

<sub> Tag Attributes

Attributes of the <sub> tag
global attributes The only attributes that can be coded on the <cite> tag are the common HTML attributes.

<sub> Tag Examples

Examples of the sub tag in HTML 5

Changes in HTML 5 - <sub> Tag

What's new in HTML 5
Differences between HTML 5 and earlier versions of HTML

The 2000-2010 Recommendations from the W3C HTML Working Group defined the HTML namespace for the sub element type name along with the names of all HTML element types. In older (pre-2000) versions of HTML, element type names were not associated with a namespace.

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