are class names in both first and second arguments of <code>m()</code>, they are merged together as you would expect. If the value of the class in the second argument is <code>null</code> or <code>undefined</code>, it is ignored.</p>
<p>If another attribute is present in both the first and the second argument, the second one takes precedence even if it is is <code>null</code> or <code>undefined</code>.</p>
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<h3 id=dom-attributes><a href=#dom-attributes>DOM attributes</a></h3>
<p>Mithril uses both the Ja