title: Is type=button necessary with aria-label?
body: <p>I read that the implicit value for a button type is <code>submit</code>. To make UI buttons, I also read that we need therefore to specify the <code>type=button</code> attribute.</p>
  
  <p>For instance:</p>
  
  <pre class="lang-html prettyprint-override"><code>&lt;button type="button"&gt;Click me&lt;/button&gt;
  </code></pre>
  
  <p>However, I've seen this example as an accessible button:</p>
  
  <pre class="lang-html prettyprint-override"><code>&lt;button aria-label="undo"&gt;&amp;#xE000;&lt;/button&gt;
  </code></pre>
  
  <p>I notice that it doesn't have the <code>type=button</code> attribute.</p>
  
  <p>If <code>aria-label</code> is defined on a button, does it implicitly mean that the button is of <code>type=button</code>?</p>
  
  <p>If not, is the above example (undo button) incorrect?</p>