Revision 79065 of Values

<h2>Lengths</h2>
<p>Several MathML presentation elements have attributes that accept length values used for size or spacing. MathML accept different units and constants for specifying lengths.</p>
<h3>Units</h3>
<table class="standard-table"> <thead> <tr> <th>Unit</th> <th>Description</th> </tr> </thead> <tbody> <tr> <td><code>em</code></td> <td>{{Cssxref("font-size", "Font-relative")} unit</td> </tr> <tr> <td><code>ex</code></td> <td>{{Cssxref("font-size", "Font-relative")} unit. (The "x"-height of the element, <code>1ex ≈ 0.5em</code> in many fonts)</td> </tr> <tr> <td><code>px</code></td> <td>Pixels</td> </tr> <tr> <td><code>in</code></td> <td>Inches (1 inch = 2.54 centimeters)</td> </tr> <tr> <td><code>cm</code></td> <td>Centimeters</td> </tr> <tr> <td><code>mm</code></td> <td>Millimeters</td> </tr> <tr> <td><code>pt</code></td> <td>Points (1 point = 1/72 inch)</td> </tr> <tr> <td><code>pc</code></td> <td>Picas (1 pica = 12 points)</td> </tr> <tr> <td><code>%</code></td> <td>Percentage of the default value.</td> </tr> </tbody>
</table>
<h3>Constants (<em>namedspaces</em>)</h3>
<table class="standard-table"> <thead> <tr> <th>Constant</th> <th>Value</th> </tr> </thead> <tbody> <tr> <td><code>veryverythinmathspace</code></td> <td>1/18<code>em</code></td> </tr> <tr> <td><code>verythinmathspace</code></td> <td>2/18<code>em</code></td> </tr> <tr> <td><code>thinmathspace</code></td> <td>3/18<code>em</code></td> </tr> <tr> <td><code>mediummathspace</code></td> <td>4/18<code>em</code></td> </tr> <tr> <td><code>thickmathspace</code></td> <td>5/18<code>em</code></td> </tr> <tr> <td><code>verythickmathspace</code></td> <td>6/18<code>em</code></td> </tr> <tr> <td><code>veryverythickmathspace</code></td> <td>7/18<code>em</code></td> </tr>  </tbody> <thead> <tr> <th colspan="2">Negative <em>namedspaces</em> are introduced in {{ geckoVersion("7.0") }} ({{ bug("650530") }})</th> </tr> </thead> <tbody> <tr> <td><code>negativeveryverythinmathspace</code></td> <td>-1/18<code>em</code></td> </tr> <tr> <td><code>negativeverythinmathspace</code></td> <td>-2/18<code>em</code></td> </tr> <tr> <td><code>negativethinmathspace</code></td> <td>-3/18<code>em</code></td> </tr> <tr> <td><code>negativemediummathspace</code></td> <td>-4/18<code>em</code></td> </tr> <tr> <td><code>negativethickmathspace</code></td> <td>-5/18<code>em</code></td> </tr> <tr> <td><code>negativeverythickmathspace</code></td> <td>-6/18<code>em</code></td> </tr> <tr> <td><code>negativeveryverythickmathspace</code></td> <td>-7/18<code>em</code></td> </tr> </tbody>
</table>