<underline>

Underline

Used to mark text that should appear with a horizontal line beneath it.

Remarks

This is normally a print consideration — not a matter for XML tagging — as underlining is frequently prohibited in online works, since it is a common “this is a link” signal.
Emphasis as a Toggle Switch: The @toggle attribute controls the behavior of this element. When the value of @toggle is set to “no”, the emphasized text remains in the requested style, no matter what the surrounding text does. When the value of @toggle is is “yes”, if the surrounding text is set to the same emphasis style, the text within this element will change to another emphasis style, so that the text will always be typographically distinct from its surroundings.
Using the element <italic> as an example, setting the @toggle attribute to “no” would mean that a material marked as italics will always be italics, even in an italic context. In contrast, if the @toggle attribute was set to “yes” on the <italic> element, if the formatting context imposes italics (whether due to another <italic> element, a stylesheet, some CSS, or other means), then the italics would be turned off within that context, making the emphasized text emphasized by contrast, but not italic. The <italic> element would still produce italics everywhere else.

Related Elements

The <underline> element is used for ordinary underlining. For underlining that involves problems with element overlap, use the milestone elements <underline-start> and <underline-end> to mark the start and end of the sequence to be underlined.

Attributes

Content Model

<!ELEMENT  underline    (#PCDATA %emphasized-text;)*                 >

Expanded Content Model

(#PCDATA | email | ext-link | uri | inline-supplementary-material | related-article | related-object | hr | bold | fixed-case | italic | monospace | overline | overline-start | overline-end | roman | sans-serif | sc | strike | underline | underline-start | underline-end | ruby | alternatives | inline-graphic | inline-media | private-char | chem-struct | inline-formula | tex-math | mml:math | abbrev | index-term | index-term-range-end | milestone-end | milestone-start | named-content | styled-content | fn | target | xref | sub | sup | x | break)*

Description

This element may be contained in:

<abbrev>, <abbrev-journal-title>, <addr-line>, <aff>, <alt-title>, <anonymous>, <article-title>, <attrib>, <award-id>, <bold>, <chapter-title>, <chem-struct>, <code>, <collab>, <comment>, <compound-kwd-part>, <compound-subject-part>, <conf-acronym>, <conf-date>, <conf-loc>, <conf-name>, <conf-num>, <conf-sponsor>, <conf-theme>, <copyright-statement>, <corresp>, <data-title>, <date-in-citation>, <def-head>, <degrees>, <disp-formula>, <edition>, <element-citation>, <email>, <etal>, <ext-link>, <fax>, <fixed-case>, <funding-source>, <funding-statement>, <given-names>, <gov>, <history>, <inline-formula>, <inline-media>, <inline-supplementary-material>, <institution>, <issue>, <issue-part>, <issue-sponsor>, <issue-title>, <italic>, <journal-subtitle>, <journal-title>, <kwd>, <label>, <license-p>, <meta-name>, <meta-value>, <mixed-citation>, <monospace>, <named-content>, <on-behalf-of>, <overline>, <p>, <part-title>, <patent>, <phone>, <prefix>, <preformat>, <price>, <product>, <publisher-loc>, <publisher-name>, <rb>, <related-article>, <related-object>, <resource-name>, <role>, <roman>, <sans-serif>, <sc>, <see>, <see-also>, <self-uri>, <series>, <series-text>, <series-title>, <sig>, <sig-block>, <source>, <speaker>, <std>, <std-organization>, <strike>, <string-conf>, <string-date>, <string-name>, <styled-content>, <sub>, <subject>, <subtitle>, <suffix>, <sup>, <supplement>, <support-source>, <surname>, <target>, <td>, <term>, <term-head>, <textual-form>, <th>, <title>, <trans-source>, <trans-subtitle>, <trans-title>, <underline>, <unstructured-kwd-group>, <uri>, <verse-line>, <version>, <volume>, <volume-id>, <volume-series>, <x>, <xref>

Example

...
<p>... Oligonucleotide primers for the amplification of TbH4 included
5&#x2032;-ATTAGGT<italic>CAT</italic><underline><italic>ATG</italic>
</underline><bold>CACCATCACCATCACCAT</bold>ACGCAGTCGCAGACCGTGACGG and
3&#x2032;-TATAGG<italic>AAGCTT</italic>CTAATCCTCGGTGTAGAGCGCCTCG. XP-1 was
amplified with 5&#x2032;-CAATTA<italic>CAT</italic><underline>
<italic>ATG</italic></underline><bold>CATCACCATCACCATCAC</bold>
AACGACGGCGAAGGAACTGTGC and 3&#x2032;-AACCTG<italic>GAATTC</italic>GTCCATGCTCACTTCGAC,
and the 38-kDa antigen was amplified with 5&#x2032;-CAATTA<italic>CAT</italic>
<underline><italic>ATG</italic></underline><bold>CATCACCATCACCATCAC</bold>
TGTGGCTCGAAACCACCGAGC and ...</p>
...