ozilla.org/en/JavaScript/Reference/Global_Objects/Boolean'>Boolean</a></span></td><td><span> true if and only if the type of this property descriptor may be changed</span></td></tr><tr><td><span class="method-depth1"></span><code>value=undefined</code><span class="pull-right label label-optional">optional</span></td><td></td><td><span> the value associated with the property</span></td></tr></table><h4>Returns</h4><table class="table table-bordered table-condensed table-hover"><tr><td>(Nothing)</td></tr></ta