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→Legal Values
<tr><td>elements</td><td>Multiple elements may be selected.</td></tr>
<tr><td>all</td><td>The contents must either be selected in entirety or none at all.</td></tr>
<tr><td>toggle</td><td>The contents are selected "following a standard toggling content model" [http://www.blooberry.com/indexdot/css/properties/extensions/nsextensions.htm].</td></tr><tr><td>tri-state</td><td>unknown</td></tr><tr><td>-moz-all</td><td>unknown</td></tr>
</table>
When the 'none' value was applied to a heading element the content could still be selected.
According to the W3C, the <i>"User agent's default style sheet may override this value. For example, user agents typically do not allow selection of the contents of a BUTTON element.</i> [http://www.w3.org/TR/1999/WD-css3-userint-19990916#user-select] As the -moz-user-select was designed to mimic the user-select property, the same applies.
== Specification Conformance ==
