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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, typically used to make the object accessible.

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 contains a detailed textual description of a visual object, intended to convey the same information a sighted user would learn from looking at the object. For interchange purposes, the description should be in this element in the XML file. For display in web-based environments, it is common to put the textual content on a separate page from the main document, and point to that display page using a URL.
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. An <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 be used as a replacement for <caption>, which is a visual element typically displayed alongside a figure, table, etc. Because a screen reader will pronounce the content of the <caption>, repeating the content of the <caption> in the <long-desc> is discouraged. If the <caption>, or the text of the article, adequately describes the meaning of the visual object, a <long-desc> is not required.
Related Elements
The similar non-visual element <alt-text> typically contains a very short phrase. The non-visual element <long-desc> contains an extended description, intended to provide the meaning in cases where a display is not possible.
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
Text, numbers, or special characters, zero or more
Content Model
<!ELEMENT  long-desc    (#PCDATA %long-desc-elements;)*              >
Expanded Content Model

(#PCDATA)*

Tagged Sample

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