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<long-desc> Long Description

Full description or summary of the content of an object such as a graphic, table, figure, or text box.

Usage/Remarks

The long description is a non-visual element used by systems such as pronouncing screen readers to make the object accessible to people or systems that cannot read/see/display the object.
Long Description Contents
This element was originally designed to contain a description, but some newer systems expect this element to contain a URI that points to such a description. Best practice is to incorporate a textual description, including or ending with an untagged URI, and repeat the URI in the @xlink:href attribute so that a link can be made.
Accessibility
Please reserve this tag for accessibility uses such as pronouncing screen readers. The <long-desc> is not a visual element; rather, its purpose is to be spoken in circumstances where the visual form of the object cannot be viewed. This element differs from the <alt-text> element in both length and purpose. The <alt-text> is typically very short, for quick scan reading by a screen reader or showing as words behind a graphic. The <long-desc> is meant for an extended description of an object such as a figure, table, graphic, etc., for example, a textual summary of a pie chart that explains both the visual form of the chart and significance of its findings.

Best Practice

The <long-desc> element should not to be used as a replacement for <caption>, which is a visual element typically displayed alongside a figure, table, etc. Thus <long-desc> should not be used to hold supplementary data. The <long-desc> is not a visual element.
Related Elements
The similar non-visual element <alt-text> typically contains a very short phrase. The element <long-desc> either contains or points to an extended description.
Attributes
content-type
hreflang
specific-use

Base Attributes

id
xml:base
xml:lang

Linking Attributes

xlink:actuate
xlink:href
xlink:role
xlink:show
xlink:title
xlink:type

Namespaces

xmlns:xlink
Models and Context
May be contained in
<array>, <chem-struct>, <chem-struct-wrap>, <disp-formula>, <disp-formula-group>, <fig>, <fig-group>, <graphic>, <inline-formula>, <inline-graphic>, <inline-media>, <inline-supplementary-material>, <media>, <preformat>, <supplementary-material>, <table-wrap>, <table-wrap-group>
Description
Any combination of:
Content Model
<!ELEMENT  long-desc    (#PCDATA %long-desc-elements;)*              >
Expanded Content Model

(#PCDATA | x)*

Tagged Sample

For a table

...
<table-wrap>
 <caption>
  <title>The Size/Price Paradox</title>
 </caption>
 <long-desc>Table is a price comparison of some
  unknown objects that are identified only by
  color as Red and Green. The price of small,
  medium, and large objects is given for each
  color, with Green objects getting cheaper with
  increasing size, from $3.25 for small to $2.25
  for medium to $1.15 for large. In contrast, Red
  objects get more expensive with size, with small
  costing $3.25, medium for $5.25, and large for $9.95.
 </long-desc>
 <table rules="rows">
  <thead>
   <tr>
    <th>Color</th>
    <th>Size</th>
    <th>Price</th>
   </tr>
  </thead>
  <tbody>
   <tr>
    <td rowspan="3">Green</td>
    <td>small</td>
    <td>$3.25</td>
   </tr>

   <tr>
    <td>medium</td>
    <td>$2.25</td>
   </tr>

   <tr>
    <td>large</td>
    <td>$1.15</td>
   </tr>

   <tr>
    <td rowspan="3">Red</td>
    <td>small</td>
    <td>$3.25</td>
   </tr>

   <tr>
    <td>medium</td>
    <td>$5.25</td>
   </tr>

   <tr>
    <td>large</td>
    <td>$9.95</td>
   </tr>
  </tbody>
 </table>
</table-wrap>
...
Related Resources